A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 123 AAT: ARC/INFO Coverage attribute table; created when vector objects are exported to ARC files. absolute colorimetric rendering: A rendering intent in which the colors in the source gamut (displayed image) that are available in the destination gamut (printer) are rendered exactly as they are and colors outside the destination gamut are replaced by the nearest available color at the outer limit of the destination gamut. White may or may not be reproduced exactly. accelerator: A key or key combination that invokes the action of some component (like a push button or menu selection) regardless of the position of the location cursor. An accelerator can activate a menu selection even if the menu is not open. accuracy: The measurement for an X-Y digitizing tablet of how close the reported coordinates for any given point come to the point’s actual location. Accuracy is stated in terms of the possible distance for error (for example, ±.01 or ±.025). active area: The area on an X-Y digitizing tablet that is sensitive to the pointing device. active element: The last vector, CAD, or TIN element added to a selection set in single select mode. If the selection set is established using a selection tool that allows multiple elements to be selected at one time, such as the rectangle or circle tool, the active element is the element with the lowest element number among those selected. additive color: Colors perceived by the human eye that are created by mixing different colors of light, or visible radiation are produced in an additive manner. The colors of the images produced on a color display screen or by a color projection onto a white screen are examples of additive color. When all wavelengths, or colors, of visible light are mixed, white light is produced. That all visible colors are present in white light is easily demonstrated using a prism, which separates white light into the spectrum of colors of which it is composed. White light can also be produced by mixing complementary colors. Absence of radiation or relatively low radiation at all wavelengths of human visual sensitivity will yield black. A predominance of radiation in a particular range of wavelengths will yield a color whose intensity is proportional to the level of radiation. (See also: subtractive color) addressable space: The memory size of a display board. This area may be the same as or larger than the viewable area shown on the display screen, depending on the display board. The object being displayed may be much larger than the addressable space. If so, TNTmips asks you to select a portion of the object to be stored in the addressable space of the display board. Some processes, such as draw processes, occur within the addressable space, rather than just the viewable space. aerial photograph: see airphoto. affine: Transformation of geodata that maps lines to parallel lines and finite points to finite points. agronomy: The study of crop and soil sciences including crop breeding, genetics, and cytology; plant molecular biology and plant molecular genetics, crop physiology and metabolism; crop ecology, production, and technology; turf grass; crop quality and utilization, agroclimatology and agronomic modeling; soil physics; soil chemistry; soil microbiology; soil fertility and plant nutrition; soil genesis, morphology, and classification; soil mineralogy; and soil management. airphoto: A photograph taken vertically from the air. Any type of camera may be used, but single-lens frame cameras are most commonly used. Airphoto images can be available to users as paper prints, transparent film, or digital computer files. An airphoto includes significant horizontal displacement introduced by camera characteristics, tilt, nearness to the target scene, and variations in elevation of the target terrain. airslide: A 35mm slide taken vertically from the air. airvideography: The growing field of making measurements from digitized frames of vertical airvideo images. These measurements can be used for managing agricultural and natural resources, making tax assessments, and monitoring environmental degradation among other uses. airvideo image: An image acquired vertically with a color, monochrome, or color-infrared video camera and recorder. albedo: “The ratio of the light reflected by a planet or a satellite to that received by it” (Random House). This definition can be generalized to any object, such as a part of the earth’s surface or atmosphere, a leaf, a soil element, and so on. algorithm: A numerical scheme applied to reach a solution of a problem. aliasing: (referring to a graphic display of lines) A line that is drawn digitally, cell by cell, with fixed, uniform color and intensity is said to be aliased. The cells are easily resolved by the observer’s eye so the line is seen to have a jagged, stair-step appearance. (See also: anti-aliasing.) allocation: The movement of materials into or out of a number of centers, all of which serve the same purpose, such as schools, fire stations, or warehouses. The Network Analysis process includes an allocate mode. alphabetic: A written language that uses a fixed, ordered set of phonetically-related characters is said to be alphabetic. Most Western European languages are alphabetic (Latin-based), as are Greek, Hebrew, Arabic, Russian, Turkish, and Indian. Modern Korean (Hangul) is an alphabetic replacement for Chinese-based character writing which was used until the 1500’s. Modern non-alphabetic languages include Chinese and Japanese, in which characters may be syllabic constructs historically derived from pictographic archetypes. While they use a basic set of characters (a few thousand) for most writing, the character set is not strictly limited to a fixed number of characters. AM/FM: Automated Mapping and Facilities Management. A geographic information system designed for the optimal processing of information about utilities and infrastructures, such as power lines and water and telephone networks. analog: Information stored and processed as signal intensity or other measurement of a continuous physical variable. Analog information processing translates and represents slight increments in data easily and conveys information by relative position without relying on the numeric value necessary to convey the same information digitally. For example, the second hand on an analog watch “sweeps” around the dial and you can tell time on an analog watch even if it has no numbers on the face. Another example is a thermometer that displays temperature using a needle or liquid can indicate fractions of a degree, as well as provide information about relative warmth by the position of the dial or height of the liquid. On the other hand, this continuous analog information is harder to copy, store, manipulate and reproduce dependably. Anyone who has ever listened to a copy of a copy of a copy of a cassette tape has first-hand knowledge of analog information degradation. For this reason, much analog information (video, audio, or field and laboratory measurements of temperature, pressure, voltage, radiation, and so on) is converted to its digital equivalent. (See also: digital, digitizer) angiogram: “An X-ray of blood vessels or lymphatics following injection of a radiopaque substance” (Random House). angle impedance: The opposition to flow around a turn in network analysis. Angle impedance is determined by node properties and your choice of lines for approaching or leaving the node. anisotropy: A distribution of point geodata in which the probability of encountering other points starting from any given point is not equal in all directions. Anisotropy can apply over short or long distances. ANSI: American National Standards Institute is a national coordinator of voluntary standards activities and acts as an approval organization and clearinghouse for consensus standards in the USA. ANSI works closely with international organizations, particularly ISO, for the development and approval of international standards. antarctic circle: A small circle of the earth parallel to the equator drawn on maps at 23° 27' from the south pole (66° 33' S). The exact location of the antarctic circle varies slightly since it is defined by the sun’s furthest southern declination (position at winter solstice) from year to year. anti-aliasing: (referring to a graphic display of lines) Anti-aliasing removes or greatly reduces the jagged, stair-step appearance of a digital line. This stair-stepping is caused by plotting a uniform color and intensity line on a display device whose minimum resolution or cell size is easily resolved by the observer’s eye. Anti-aliasing smoothes out the jagged edges of the line by filling in some of the intermediate and flanking cells in lower-intensity colors. (See also: aliasing) API: An Application Program Interface is a set of system calls or routines for application programs to access services from operating systems or other programs. API is fundamental to client/server computing. APPLIDAT: A unique combination of SML scripts and Project File geospatial data created in TNTmips. An applidat (APPLIcation plus DATa) can be launched from a desktop icon that opens the preselected geodata and presents a custom icon toolbar. arbitrary georeference: A georeference that uses a matrix rather than control points. Raster, vector, CAD, or TIN objects can have an arbitrary georeference. An arbitrary georeference is created when an object with no georeference is used as a reference layer for creation of a new object in the Spatial Data Editor. Note that you can make an object without a georeference in the Editor. An arbitrary georeference allows you to correctly display related objects together. archive: A preserved collection of historical information, such as a backup of your data. ARC/INFO: A vector-based Geographic Information System (GIS) developed and marketed by ESRI, Inc. for use on workstations. ARC/INFO extent file: The name of the data file used by ARC/INFO which contains arc, node, and polygon data elements. arcsecond: “The sixtieth part of a minute of angular measure often represented by the sign “, as in 30”, which is read 30 seconds” (Random House). (See also: degree, minute.) arctic circle: A small circle of the earth parallel to the equator drawn on maps at 23° 27' from the north pole (66° 33' N). The exact location of the antarctic circle varies slightly since it is defined by the sun’s furthest northern declination (position at summer solstice) from year to year. Area correlation: A DEM extraction method that methodically traverses a pair of stereo images, working from the initial set of correlation points supplied by the user, and building a correlation model from new points of correlation that it finds. arrow glyph: A graphic symbol on a cascade button that indicates the direction in which the button will open its associated cascade menu. ASCII: American Standard Code for Information Interchange (pronounced “askee”). The 7-bit (128 characters) used as a computer’s alphabet. The Latin alphabet character set encoded into digital values between 0 and 127 includes lowercase and uppercase letters, the numerals 0–9, English punctuation marks, special symbols (such as @#$%^&*) and non-displaying characters often used as printer control codes. The eighth bit, giving values from 128 to 255, is used in a nonstandard fashion and is not part of the standard ASCII code. PCs normally have the “extended” character set in their system font for digital values from 128 to 255. The characters used for values from 128 to 255 for TNTmips display screen fonts are unpredictable but can be displayed in the font style window. Some fonts have no characters in this range while others have characters for some or all of these values. ASCII is a proper subset of Latin-1, Unicode, and ISO 10646, which are the 1-byte, 2-byte, and 4-byte standards for international character encoding. The term “ASCII file” is often used to mean a text-only file. Documents in most word processors are not text-only files, since they include header information and formatting characters. However most word processors have an export or print-to-file utility that will convert a document into a text-only ASCII format. ASCII file: A text-only file. Documents in most word processors are not text-only files, since they include binary header information and formatting characters. However most word processors import so-called ASCII files and have an Export, Save/Text-only, or print-to-file utility that converts a document into an “ASCII” format. However, these files are not true ASCII files because they may include the characters from 128-255. The characters in this range are different between platforms such as PCs and Macintoshes and even from font to font with a platform, and are not part of the standard 7-bit ASCII code. (See also: ASCII.) ASCS: Agricultural Stabilization and Conservation Service. aspect: A parameter that is associated with a feature of a topographic or other three dimensional surface. Aspect is the compass direction (usually from north) for the perpendicular to the tangent to the surface at some selected point. Aspect tells which direction a surface slopes measured in degrees from North in a clockwise direction. aspect ratio: The ratio of horizontal scale to vertical scale for printing or display. For graphics and image processing, square cells/pixels are best (aspect 1:1). Some display devices have a non-square aspect, which causes images to appear stretched or distorted. Standard broadcast video has an aspect ratio of 4:3, which must be corrected in any framegrabbing or other digitization process. assignment statement: (in database query) A line in a query that changes the value of a style drawing variable. Example: size = 5. That statement changes the value of the size variable to 5. (The size variable controls the size at which node elements are drawn). Assignment statements may be used in vector display and several other processes that let you assign drawing styles by query. attribute: A piece of information describing an element in a coordinate data object or a raster cell. Each element in a vector, CAD, or TIN object may be assigned one or more attributes. Element attributes include internal information and information in an associated database. Attributes can include such qualities as drawing style, element number, and classification category, such as “intermittent stream” or “wetland.” attribute table: A tabular object containing records and fields, or rows and columns. Each record, or row, represents one or more geographic features and each field, or column, represents one attribute of those features. authoring station: A computer with the TNTmips software and a key authorized for the HyperIndex Linker software (available as a TNTmips software extension). In addition to viewing HyperIndex stacks, an authoring station has the ability to create and maintain stacks. The intention of providing the HyperIndex Linker software separately is to make it easier for organizations to eliminate data corruption by controlling who has the authority to create and edit stacks. (See also: HyperIndex, stack.) AutoCAD: The most popular commercial Computer Aided Design (CAD) software package. Written and distributed for the microcomputer by Autodesk, Inc., this software supports the same display boards as TNTmips with its own display drivers. autocorrelation: “The correlation of an ordered series of observations with the same series displaced by the same number of terms” (Random House). auto-correlogram A process in Hyperspectral Analysis. The Auto-Correlogram process provides an estimate of the spatial-spectral variability of the hyperspectral image on a pixel by pixel basis. AVHRR imagery: Advanced Very High Resolution Radiometer imagery produced by NOAA satellites. AVIRIS imagery: Airborne Visible/InfraRed Imaging Spectrometer imagery. Multispectral images of approximately 240 coregistered spectral bands collected by NASA aircraft. azimuth: The angle defined by the intersection of a map’s central line of projection with any meridian. If a map projection uses a central line that is oriented to true north, such as a standard meridian, the azimuth angle is zero. azimuth angle: Angular displacement from North. azimuthal projections: (also known as Planar Projections) A class of map projections that are constructed by placing a flat planar surface tangent to a single point on the globe, or by placing the globe to an intersecting (secant) plane. With azimuthal (or planar) projections, lines of equal distortion are concentric around the point of tangency or the center of the circle of intersection. Most azimuthal maps do not have standard parallels or standard meridians. Each map has only one standard point: the center. Thus, the azimuthal projections are suitable for minimizing distortion in a somewhat circular region, such as Antarctica, but not for an area with predominant length in one direction. Azimuthal projections include Orthographic, Stereographic, Gnomonic, Lambert Azimuthal Equal-Area, and Azimuthal Equidistant. azimuth spacing: The linear distance or image scale in the along-track dimension, which is perpendicular to the range directions in a radar image. The resolution of a synthetic aperture radar (SAR) image in the azimuth direction is constant and independent of range. — B — backup: A copy of a file, set of files, or whole disk for safekeeping in case the original is lost or damaged. band or spectral band: A range of wavelengths of electromagnetic radiation. Remote sensing devices commonly collect images in discrete bands, such as visible red, green, and blue, and the invisible near-infrared. band interleaved: A type of geodata storage and reading for multiple bands. The geodata is stored and read line by line. That is, the first line of the first band is followed by the first line of the second band, the first line of the third band, and so forth through all bands . Then the next line stored is line two of the first band followed by line two of the second band and so forth through all lines within all bands. band mapping: A spectral matching method in Hyperspectral Analysis. The Band Mapping method compares unknown spectra that you are analyzing to spectra in a reference spectral library on the basis of the positions and relative depths of absorption features. band trailer bytes: Some image bands have trailer information attached to the end of each band image. In the User-defined Raster Import process a user must tell the import process the length of this trailer in bytes so that the import process can import the trailer information correctly. band variance: One of three noise statistics plots that can be produced in the Hyperspectral Analysis process. The band variance plot shows the proportion of the variance, or noise, that can be attributed to each input band. bandwidth: A measure of the volume of data that can flow through a communications link, or throughput. Bandwidth is measured in kilobits or megabits per second. (Kb/s, Mb/s). Also, a section of the electromagnetic spectrum between two frequencies. For example, AVIRIS collects 224 contiguous spectral bands with a bandwidth of 0.10 micrometers. barrier: A node that can not be crossed in the Network Analysis process. batch: (DOS) A DOS batch file is a text file with the extension .BAT that contains one DOS command on each line. When you enter the name of the batch file at the DOS prompt, the system performs each command in turn. batch: (TNTmips) A process or sequence of processes that is set up to run unattended and requires no user interaction or supervision. Many computationally intensive TNTmips processes let you set up a series of jobs in a batch. TNTmips also offers a batch utility that lets you string together batch jobs from several different TNTmips processes. bathymetry: The science of measuring ocean, sea, and lake depths. baud rate: The speed of data transmission between a computer and other devices measured in bits per second. Bézier curve: A polynomial curve bounded by four points, which form a “bounding box.” Manipulating the position of the bounding points lets a user stretch and position a smooth curved line in the design of a graphic shape, such as the irregular curving outline of a font character. bilinear interpolation: A mathematical method for interpolating a new cell’s value within a 2 x 2 neighborhood of cells. Bilinear interpolation is used in resampling a raster object to create a new raster object with a different cell size, orientation, or internal geometry. (See also: interpolation.) binary: A base 2 number system that uses only the data values “0” and “1.” Each place represents a power of 2, so, for example, the decimal number 6 is represented in base 2 as 110 (= 1x4 + 1x2 + 0x1). binary raster object: A raster whose cells contain only the values “0” (typically displayed as black) or “1” (white). Binary raster objects usually store a scan of black lines on white paper, the results of thresholding a byte-oriented raster object into two data ranges, a threshold of a particular color range, or a data mask. biomass or total biomass or total plant material: The amount of plant material per unit of ground area, recorded either as wet weight or dry weight. It is usually expressed in grams per square meter, tons per acre, or metric tons per hectare. bit: The smallest unit of computer data having a single value of either “1” or “0”. A contraction of the two words “Binary” and “digit”. Binary data is 1-bit data. Computers normally manipulate bits at least 8 at time. A group of 8 bits is called a byte. A computer’s processing power is often measured by the number of bits it handles at once. The earliest PC’s were 8-bit machines. More recently processors and data structures for 16-bit, 24-bit and 32-bit data have become common. bitmapped font: A font specification in which each character is described pixel by pixel for a particular font size. Thus, bitmapped fonts do not rescale easily: at smaller sizes, pixels are left out, and at larger sizes, pixel reduplication causes a jagged, blocky, low-resolution appearance. Bitmapped fonts cannot be created or edited in the Outline Font Editor and are not available for use in the TNTmips layout and annotation processes. (See also: outline font.) bits per pixel or pixel depth: The number of data bits each pixel represents. In 8-bit contexts, the pixel depth is 8, and each display pixel can be one of 256 possible colors or shades of gray. With a 24-bit raster (or with three coregistered 8-bit rasters) the pixel depth is 24, and 16,777,216 colors are possible. BLM: Bureau of Land Management of the USDI. BLOB: Bianary Large OBject. The data type of a field in an RDBMS table that can store large image or textual data as attributes. block: A block is a grouping of CAD elements and attributes that can be manipulated as a whole. All CAD objects contain at least one block, the Main Block. When a block (such as the detail for a door frame) is used multiple times in a drawing, the block description is stored once, and each insertion point refers to that source. block insertion element: A block that is inserted into another CAD block and, thus, acts as an element. board or interface board: An electronic circuit board installed in a microcomputer to add hardware features. (See also: display board.) Boolean expression: A type of expression that reduces to a logical (true or false) condition that contains logical expressions (e.g., Flowrate > 50) and Boolean operators. Boolean operators: An operator that specified how to combine simple logical expressions into complex logical expressions, such as OR, AND, and NOT. For example, Flowrate > 50 AND Depth < 100. Exclusive Or (XOR) and AND NOT are also Boolean operators. boxcar classification or boxcar interpretation: The simplest form of automated image interpretation whereby three data ranges are selected for three coregistered images (like red, green, and blue). The three data ranges define a boxcar shape if plotted on three dimensional perpendicular axes that represent possible data values in red, green, and blue. The ranges are usually selected to represent the color variation in the three rasters for a feature of interest (like all the dark brown areas representing bare soil). All of the data triplets in the three raster objects are tested to determine if they represent a cell inside the boxcar. All the inside cells may then be displayed or otherwise recorded as “classified.” Boxcar classification is not restricted to sets of three rasters. It may be used with any number: using 2 rasters designs a 2-dimensional “boxcar” test in a 2-dimensional space, and using “n” rasters defines an n-dimensional “boxcar” test in n-dimensional space. box cursor or location box: Marks the focus for keyboard activity in a window. breakline: A linear feature that controls the surface behavior of a TIN in terms of smoothness and continuity. Breaklines are always maintained as linear features in a TIN. brightness: The physical property indicating how much electromagnetic radiation is being reflected or radiated by a chosen point. Brightness is similar to the HIS property of Intensity, and is used in the HBS color model. Brightness is also the property computed from Landsat MSS or TM images by Kauth’s greenness, brightness, wetness transformations. (See also: HBS, HIS.) BSpline : A curved smoothing that can be applied to a line. A BSpline is calculated by a polynomial equation. Different types of BSplines, such as Cubic BSpline and Quadratic BSpline, can be calculated from different types of polynomial equations. bubble: A small island (often just a cell or two) of background color in the stream of a thinned, binary line in a raster. Bubbles are artifacts of the thinning process and result from binary lines that include unnoticed cells of the background color after thresholding. Bubbles must be repaired by raster editing or else the automatic vectorization process will create small, incorrect polygon elements from them. buffer: A portion of computer memory set aside for quick temporary storage. A buffer is commonly used to store data on its way to or from a hardware device such as a disk drive. The buffer lets the computer “save up” access operations and not be slowed down by waiting on the hardware to respond at every step. buffer zone: A border area that acts as a barrier separating or surrounding an area designated for special protection. Some states have legislated buffer zones around certain wetlands to prevent damage to the local ecosystem. bug: An error in a computer program or in a piece of electronics that causes it to malfunction. MicroImages prefers to call these by their real name—errors. building points: Creating and/or adding points in a vector object from imported coordinate data (like text files that contain pairs of coordinates, or database files with fields representing pairs of coordinates). bus: The circuit channel or path a computer uses to move data and send signals between devices. A microcomputer’s bus architecture determines what kinds of peripheral circuit cards can be plugged into its expansion slots. DOS and OS/2 computers have four varieties of bus architecture: PC, AT (also called ISA), EISA, and Micro Channel. The original PC bus handles 8-bit data. The AT bus doubled the data width to 16 bits and became the industry standard (thus ISA, for Industry Standard Architecture). IBM introduced the PS/2 with a proprietary bus, the 32-bit Micro Channel. Other vendors countered with a 32-bit Extended ISA (the EISA). The PC/ISA/EISA buses are backward compatible: that is, expansion cards designed for an older bus will normally work in a newer bus slot. Thus, an 8-bit display board from a PC bus works in a 16-bit ISA slot or a 32-bit EISA slot, but a 16-bit display board for an ISA bus does not work in an 8-bit PC slot. button: A control component in a window that is activated by positioning the mouse cursor over it and pressing the left mouse button. A button may be one of several types: push button, radio, toggle, check, cascade, or option. B/W photo, B/W image, B/W display, or B&W: A black and white photograph or some other monochrome image rendered in black, white, and shades of gray. byte: A data element made up of 8 bits and having 256 possible values. In text-oriented processes, each byte represents one character of text. In 8-bit raster processes, each byte represents one cell value and may correspond to one pixel on the image display. (See also: bit, exabyte, gigabyte, kilobyte, megabyte, pecabyte, terabyte, yottabyte, zettabyte.) byte-oriented or 8-bit raster object: A raster in which each cell is represented by one byte (8 bits) and can therefore assume 256 possible values. C and C++: High-level programming languages. CAD: Computer Aided Design. CAD originated on larger, dedicated workstations and minicomputers and has now migrated to microcomputers. In its simplest sense, CAD is used for computerized drafting. Many CAD systems also provide more advanced features like solid modeling and simulation. cadastre: “An official register of the ownership, extent, and value of real property in a given area, used as a basis of taxation” (Random House). CAD Editor: The process used in TNTmips for creating and editing CAD objects. Input can be from your computer’s mouse or from an X-Y digitizing tablet. CADkey: A popular commercial microcomputer Computer Aided Design (CAD) software package from CADkey, Inc. CAD object: A CAD object, in RVC format, like a vector object, is composed of coordinate data, but uses a different data structure. A CAD object has a free-form topology, so it may be useful for applications that do not require an exact description of the relationships between the elements in the object. CAD object topology does not reconcile things like line intersections, polygon overlap, and polygon islands. A CAD object also allows for descriptions of geometric shapes. For example, in a vector object, a circle is always stored as a polygon, and at a high enough magnification, the discrete point and line elements become visible. By contrast, a CAD object stores a circle by its center point and radius. Thus, at any magnification, it looks circular. Since they have reduced topological constraints, CAD objects generally require less storage than their vector object counterparts. [See also: element (CAD).] calibrate or cell size calibration: To establish scale or cell size (for a raster) for an object in a project file. Once a raster, vector, or CAD object has been calibrated, accurate measurements can be determined and displayed. (See also: georeference) calibrated image map: See: image map. cap style: The ends of dashed line segments, which are components of line patterns, are caps. You can assign a style to this cap when you are creating or editing a line pattern in the Style Editor. The cap can be round or flat. capacity: The number that can be accommodated by a center in network analysis, such as the number of students a school can accommodate, the quantity of perishable goods that can be delivered in one day, the number of seats in a theater, or the number of parking spaces at a shopping mall. Cartesian coordinate system: A two-dimensional, planar coordinate system in which x measures horizontal distance and y measures vertical distance. Each point on the plane is defined by an x,y coordinate. Relative measures of distance, area, and direction are constant throughout the Cartesian coordinate plane. capture: To freeze and digitize a standard video input signal (such as VHS tape or broadcast video). Some microcomputer display boards offer video capture. (See also: frame-grabbing.) cartography: The art or science of making maps. CartoScript: A script written with the cartographic scripting language in the TNT products, which provides a complete and flexible set of drawing functions that allow you to design custom map symbols for many applications. cascade button: A type of button that displays a cascading menu. A cascade button is typically a selection on a parent pulldown menu. It includes an arrow graphic that points in the direction the cascading menu appears. cascading menu: A submenu that opens from a selection on a parent pulldown or popup menu that provides selections that amplify or supplement the parent selection. categorical data: Data in a raster object is said to be categorical if it cannot be represented by a continuous surface, since intermediate terms cannot be derived with meaningful results. Example 1: soil type data cannot be interpolated, since a soil type 14 and a soil type 15 cannot sensibly be averaged to derive a soil type 14.5. Example 2: feature classification data cannot be interpolated, since a cell assigned membership in the feature “corn” cannot sensibly be used in any process that averages it with a cell assigned membership in the feature “wheat.” Do not confuse the terms “categorical data” and “category”—they have different and distinct meanings. category: (in Feature Mapping) A subdivision within a region of interest (which also has a particular meaning in reference to Feature Mapping) that lets you divide the study site so that the measurement data in the output text file will be organized geographically. So, if you have defined a region of interest as the wetland duck habitat along a river floodplain, you might want to divide the wetlands into categories: perhaps ownership areas (like refuge lands, private ownership, and easement areas). Then the text output file would break down the wetland feature measurements by ownership area. If you do not define categories, TNTmips treats the entire region of interest as a single category (and does not subdivide the feature measurements in the output data). Do not confuse the terms “categorical data” and “category”—they have different and distinct meanings. CAT scan: A medical diagnostic image produced by Computer Aided Tomography. CCITT Comité Consultatif Internationale de Télégraphique et Téléphonique (International Telegraph and Telephone Consultative Committee): A standards organization that has developed a series of communications protocols for the facsimile transmission of black-and-white images over telephone lines and data networks. The CCITT acronym in TNTmips represents a type of lossless raster compression that is used for 1-bit images. CD-R: Compact Disk-Recordable. A 5" optical disk that can be written to by a CD burner. CD-ROM: Compact Disk, Read-Only Memory. A 5" optical disk containing prerecorded data sets. CD-RW: Compact Disk-Rewritable. A 5" optical disk that can be written to by a CD burner in multiple sessions. cell: One value in a raster that corresponds to a specific area on the ground. A raster cell may contain a value that describes the elevation above sea level at one position in a survey site or the intensity of red radiation for a pixel in a video image. For convenience, a raster cell is usually thought of as square or rectangular, although many image collection devices actually measure circular or elliptical areas. If a raster object is created from a screen image, each cell value represents one pixel. cell size: The dimensions of the area on the ground to which a raster cell value applies. A cell size of 30 meters signifies that the value in each cell of the raster object applies to a 30 x 30 meter area in the study site. cell size calibration: The transfer of cell size information to a raster. center: A point within a network to which materials or people are brought or from which materials or services are distributed. central meridian: The north-south meridian of a map projection around which the map is centered. centroid: “The point that may be considered as the center of a one- or two-dimensional figure, the sum of the displacements of all points in the figure from such a point being zero” (Random House). CGA: Color Graphics Adapter. An early microcomputer graphics subsystem developed for the IBM PC. The CGA was hampered by low resolution and limited color selection. It has been largely superseded by the EGA and the newer VGA. (See also: EGA, VGA) CGI: Common Gateway Interface. CGM: Computer Graphics Metafile is a graphic image exchange standard. change image: An image produced using raster algebra that shows change over time between coregistered images. character: An element used for the graphic representation of data (such as a letter, numeral, or symbol) or control of data (such as a tab, space, return, or enter). Each element has a corresponding character code in the Unicode table. check button: A square button in a pop-in window that presents one selection in a group of on/off options. When a check button is “on,” it appears “pushed in”. Clicking on one check button does not effect any other check buttons in the group. (See also: radio button.) chip: Commonly, any integrated circuit logic component of a computer. The two broadest categories of chips are memory chips and processor chips. Most DOS microcomputers use main processor chips developed by Intel Corporation (the 8088, 8086, 80286, 80386, 80486 series). CIR image: Color-infrared image. Color-infrared images may be collected by an electronic scanner or a camera that uses special film with sensitivity from green through infrared. The photographic infrared radiation just beyond the range of human vision is then displayed as red. Normal red from the scene becomes green, and green becomes blue. Normal blue in the scene is filtered out and not recorded. CIR images are used to show the vigor of plant life. Healthy vegetation appears red, while distressed or damaged vegetation may look pink, tan, or yellow. (See also: color-infrared image) class: (raster) A set of all image features of the same type. As part of the interpretive process, the user names a class to identify the type of material it contains, like “corn,” “bare soil,” “wetland,” or “urban.” In a set of coregistered raster objects, a grouping of cells with similar sets of values. A class normally corresponds to a specific land cover type with a restricted set of biophysical properties. class center: The set of raster values that define the mean vector for the class in feature space. classification: Grouping cells (often by color characteristics) from coregistered rasters to map the location and type of image features (like type of crop, surface cover, and map line type). class list: A subobject containing a list of classes associated with a vector or CAD object. client/server: A software system has a client/server architecture when there is a central processor (server) that accepts requests from multiple user processes (clients), such as TNTserver and TNTclient. clip: Clipping limits the extents of a layer or group for the purpose of display. Clipping extents can match a reference object or use geographic coordinates. clip art: Icons, symbols, and drawings distributed in computer-readable format. Computer clip art was popularized by the Apple Macintosh, which can use published clip art for electronic cutting and pasting into drawings or pages of text. TNTmips users can similarly create and share a variety of original symbols, patterns, and line types. clump: A set of contiguous line, node, and polygon elements in a vector object. clustering: A process in which multiple, registered, overlapping, rasters are reduced to a single raster, which is referred to as a cluster map. The rasters used in clustering represent analytical data (such as images and elevations). Different clustering methods (such as K-means, Fuzzy C-means, and Isoclass) use varying logic to accomplish this mapping and dimensional reduction. In general, all of the methods use the concept of testing multiple values for each cell against all other cell values to determine which subpopulation each cell is most similar to and should be grouped with. All clustering methods first make a preliminary set of groups by testing all cells or a sample of them. They then proceed by various methods to test individual cells and dynamically redefine the clusters until every cell is satisfactorily assigned a cluster membership in a single cluster, which is recorded at that cell’s position in the cluster map. The maximum number of clusters to form and the number of refinement iterations is usually controlled during setup. (See also: labeling, unsupervised classification) cluster labeling: Identifying and grouping the clusters in the cluster map raster object that result from any kind of automated image interpretation. The user chooses labels (names for types of features) based upon his or her knowledge of the areas or materials in the image. Use the TNTmips Feature Mapping process to label (and possibly combine) the clusters. cluster map: The output raster created by clustering or by unsupervised classification. The clusters are usually identified or labeled as some useful type of material (for example, an agricultural crop, a body tissue type, or a soil type). It is important to note that this raster does not contain values that can be subjected to further mathematical analysis because the clusters and their reidentification as material or area types do not represent data values that are mathematically continuous. For example, cells in a cluster arbitrarily assigned the value of 4 by the clustering process does not necessarily represent twice as much of something as a cell assigned to a cluster that was given a value of 2. CMY or Cyan-Magenta-Yellow: The standard set of subtractive, processing colors used in printing. Color printing devices use discrete dots of cyan, magenta and yellow to present the appearance of a full-color image to the human eye. The combination of cyan, magenta and yellow produces black. However, some printers include black ink along with the above three colors, which is properly called CMYK. CMYK or Cyan-Magenta-Yellow-Black: See CMY or Cyan-Magenta-Yellow. CMYKcm: Used with six color printers. Cyan-Magenta-Yellow-Black-Light Cyan-Light Magenta. coextensive: Covering the same ground area exactly. If two raster objects are both coregistered and coextensive, there is a 1:1 cell correspondence for ground area coverage in each cell of the rasters. COGO: The Coordinate Geometry (COGO) process includes COGO commands that when executed accomplish meaningful functions for professional surveying and civil engineering applications. COGO by definition is a command structured problem oriented language and computer program for the solution of geometric problems. COGO tools are useful for creating or editing vector or CAD objects with land surveying, global positioning system, and other precision data. The COGO approach has been used by surveying and civil engineers since approximately the early 1960’s. COGO relates to the LOGO language used in early computing and permits the creation of precise control and descriptive data entry into new or existing objects tied to the ground surface, projection, and datum. COGO points and the objects defined by those points, can be determined in 3D space within the interior of an object (for example rooms and hallways in a building; adits, shafts, and various tunnels in an underground mine; locations in a timber stand; or areas in a hydro-geologic environment) and can be used to define interior surfaces in vector applications and solid objects in vector and CAD applications. color balancing: Adjusting the intensities and distribution of red, green, and blue to create an image with a particular color appearance for display or printing. color compression: Removing duplicate (in some cases near-duplicate) colors from a color map to make room for new colors. color depth or pixel depth: The number of data bits each pixel represents. In 8-bit contexts, the pixel depth is 8, and each display pixel can be one of 256 possible colors or shades of gray. With a 24-bit raster (or with three coregistered 8-bit rasters) the pixel depth is 24, and 16,777,216 colors are possible. color-infrared (CIR): Color-infrared images may be collected by an electronic scanner or a camera that uses special film. Infrared film records the photographic infrared radiation just beyond the range of human vision as red. Normal red from the scene becomes green, and green becomes blue. Normal blue in the scene is usually filtered out and not recorded. Any physical or biological damage to growing plants which begins to cause a deterioration in their vigor (their water and/or chlorophyll content) causes a rapid decrease in their reflectance of photo-infrared radiation, and increases in their red reflectance. CIR photographs show these changes much sooner and more dramatically than normal photographs or human eyesight. Healthy, green vegetation appears in bright red, while damaged, diseased, or dying vegetation appears in shades of pink, tan, and yellow. This knowledge was first used during the Second World War when color-infrared film was called camouflage detection film. It provided pre-visual detection of the changes in vegetation cut or damaged by military activity and could very easily separate color-camouflage materials (like olive drab canvas) from live foliage. color map or color table: A color map is the table, or map, used by a computer system to assign display colors to digital values. A color map for an 8-bit raster object can contain a total of 256 colors. A gray scale image may have a color map with 256 shades of gray, ranging from black (0) to white (255). The first 64 places in a color map are normally assigned to the “standard 64” annotation colors. Additionally, certain processes may use 16 values for standard shades of gray. The remaining 176 or 192 colors are then available for the image colors used in the display. Some types of color maps that you will encounter in TNTmips are optimized color maps and composite color maps. color map editor: A TNTmips window which shows a table of the current display colors. With 8-bit data and devices, this palette includes 256 colors in 8 rows and 32 columns of color cells. On 16-bit devices, all 4096 colors normally appear. color separation: Manipulating a full-color image in order to extract features of one color or range of colors. The color separation process can be used to create a binary raster object from a composite color raster object (or a set of three RGB raster objects) to lift out blue line images, for example, leaving behind background colors and lines images of other colors. Printers use related color separation techniques to prepare process color separates from full-color originals. column: A vertical list of data values or display cells in a raster object or display. command: A specific instruction to a computer program entered by the user to perform a desired action. COMMAND.COM: A file that contains the internal DOS commands required at PC startup. This file is transferred when a disk is formatted as a startup disk. command prompt: Formerly called the DOS prompt on PCs, it is path:> found in a DOS shell. component: Any single element in a window, including buttons, fields, scroll bars, sashes, panels, menus, panes, frames, dialog boxes, or separators. compose sequence: A sequence of two or more keystrokes used to create a single character, as in the case of European languages that have characters with various diacritical marks. composite color raster object: A raster object in which each cell contains a data value representing one of the colors into which all available color data for that cell has been compressed. For 8-bit raster objects, there are 256 possible colors for each cell; for 16-bit raster objects there are 32,768. Composite color rasters are usually compressed from a red/green/blue raster set that retains a wider range of color information. The composite raster still produces near photographic quality color displays. composite color video: The standard color video output of a VCR or video camera that adheres to the NTSC video standard. All the color information is contained in one signal (instead of in the three RGB color signals). computed field: A field in a database table with a value calculated from the values of other fields in the same or different tables of a single database. You define the expression used to generate the values for a computed field using the same language and syntax employed for database queries. The appropriate record values for use in a computed field are determined through primary and foreign key relationships or by element attachment. conflation: Determining a single resultant line from coincident or nearly coincident lines while merging or editing vector objects. conic projections: This group includes projections that are constructed by placing a cone tangent to the globe along a standard parallel in the mid latitudes, or in the case of a polyconic projection, placing a cone secant to two (or more) standard parallels. Conic projections are commonly used to depict hemispheres or smaller portions of the earth’s surface. continuous data: Data in a raster object is said to be continuous if it can be represented by a three-dimensional surface such that intermediate values can always be derived with meaningful results. Example: an elevation raster has continuous data because an elevation of 400 and an elevation of 500 can fairly be averaged to assign an intermediate elevation of 450. continuum: Continuous extents with no obvious division into parts. contour map: A topographic map that uses contour lines to portray relief. Contour lines join points of equal elevation. contours: Lines on a contour map or other isomorphic map that identify levels of a parameter at specified, discrete intervals. contrast: The difference between bright and dark values in the display or printout of a continuous tone (usually grayscale) image. The stronger the contrast, the more difference between the brightest and darkest values. Most images benefit from a process of contrast enhancement, which artificially increases the contrast. TNTmips provides different methods of distributing intermediate display or print values. The Linear contrast model assigns straight-line increments of intensity. Many images look better when they are produced with the Normalized contrast model, which assigns intensity increments according to a normal distribution curve. contrast table: A contrast table assigns display intensity values to raster object cell values using a specified translation method, such as linear or normalized translation. The type of translation chosen and the limits defined will change the display values but, in general, the result is to increase the apparent differences between the majority of cell values, which usually fall within a narrow range. control panel or panel: An area of a window that holds related buttons, sliders, fields, and other components used to govern the behavior of a process. control point: Points, elevations, and/or cells which are used to establish map coordinate control for ungeoreferenced objects or objects that are to be used in a process such as Stereo Modeling. In the manual mosaic process, a control point is a feature in a piece of the mosaic (such as a road intersection) for which the map coordinates are known. In the raster-to-vector calibration process, a control point is a feature that is co-located between the ungeoreferenced raster object, and the georeferenced vector object overlay. A control point may be something like a bend in a river or a road intersection that shows on both a raster object and an overlying vector object. Tying control points together lets TNTmips adjust scale, orientation and geometric distortion between rasters and vectors. TNTmips’ georeferencing and registration processes rely on control points introduced and identified on the display with the mouse. (See also: tie points) control point list: One type of map registration subobject (Regist) that contains a paired list of map coordinates and cell coordinates. TNTmips uses the control point information to derive map calibration for the entire object. (See also: linear transform) controls window: The TNTmips display and edit processes always include at least two windows: the controls window and one or more view windows. A single controls window can govern multiple view windows. convolution: Mathematically determining the data value for a new cell in an m x n neighborhood of cells. Raster filtering, resampling, and other raster processes use convolution. Convolution processes should never be applied to raster objects that contain categorical data. Convolution is only appropriate for continuous data. co-occurrence raster: A raster created in the Color Binarization process. The cell values in the co-occurrence raster are the frequencies of occurrence of the same cell value in adjacent cells in the input raster object. The Color Binarization process analyzes groups of eight neighboring cells in the input raster object to determine the occurrence of the same cell value within the group of cells. coordinate: A set of numbers that designate position in a given reference system, such as X-Y in a 2D coordinate system and X-Y-Z in a 3D system. coordinate system: A reference system for defining precise locations on the earth’s surface. Coordinate systems may be independent of or tied to a particular map projection. coprocessor: Older microcomputers used for heavy computational tasks have a second microprocessor, called a math coprocessor. To speed things up, the main CPU assigns its tedious arithmetic to this helpful specialist in much the same way that modern accountants use calculators for the computations their grandfathers did by hand. In the Intel CPU series, the main processor’s chip number ends with the digit 6 and the coprocessor’s chip number is the same except for the final digit 7: 80286 / 80287; 80386 / 80387. With the 80486, Intel included the math coprocessor in the basic design. (Thus there is no 80487). coregistration: The condition in which associated raster and/or vector objects overlay each other with correct orientation and geometry so that corresponding internal features align. correlation: The degree of relatedness between two objects; more specifically, the degree to which one value in a set of values can be used to predict the corresponding value in another set of values. correlation points: (also called tie points). A pair of points collocated on a common feature, such as a road intersection, in a pair of images. A set of correlation points defines the mutual spatial relationship of a pair of overlapping images without regard for their real position in a map coordinate system. cost raster: A cost raster is a raster object with cell values that represent a price per distance unit; for example, monetary expenditure per meter, fuel usage per mile, traversal time per mile, and so forth. coverage file: See: pcARC/INFO coverage file. CPU: Central Processing Unit. The main computing engine of a computer. CRT: Cathode ray tube. cross validation: An option in the Kriging method of Surface Fitting in the Surface Modeling process. This option is a pre-processing function that calculates the mean error and standard deviation for estimated control points compared to the actual control points. cubic convolution or cubic interpolation: A computationally intense interpolation method used in raster resampling. This method determines a new cell value to produce a smoother result by fitting a cubic polynomial surface to a 4 x 4 neighborhood of cells. Bilinear interpolation normally produces results which are almost as good. Cubic convolution should not be applied where the mean data value for a group of cells is undefined as in categorical data (like an 8-bit color raster object, a classification map, or any raster object containing similar category-type data). cursor: See: mouse cursor, text cursor. cursor hot spot: The pixel location on a cursor shape at which the cursor activity takes place. For example, the hot spot on an arrow cursor is at the point of the arrow, while the hot spot for a cross-hair cursor is at the intersection of the crosshairs. cylindrical projections: This group of projections includes all projections constructed by placing a cylinder tangent to the globe along a standard parallel—usually the equator, or secant to the same standard parallels in opposite hemispheres, respectively. Cyrillic: An alphabet widely applied to the Slavic languages, as in the case of the thirty-three-letter Russian alphabet. Since the 1930’s it has been used for most of the languages of the former Soviet Union. (Attributed to Saint Cyril, a ninth-century Christian apostle of the Slavs.) dangling line: A dangling line element intersects another line element on only one end. The unattached end terminates in a node element that is not shared by another line element. Dangling lines may be either overshoots or undershoots. Dangling lines can be avoided by using the snap options when editing. database form: A database form allows you to reorganize the information in a table for display in single record view. This reorganization may include changing the order and placement of fields and / or displaying only selected fields from an existing database table. You can also modify field titles to include spaces, which are not allowed in actual field names, to exceed the 15 character maximum, or you can change the name entirely if the original seems too cryptic for the intended audience. You can also add text that is not associated with a particular field to provide logical groupings for the information presented in the form. A database form cannot exist without an accompanying database table. Editing in the default table layout or in any of the forms created as an alternate means of viewing the same information alters the single set of values used in all cases. Database forms are stored as subobjects of the database. database object or dBASE object: A database is a collection of information related by some unifying theme, such as demographics, epidemiology, or geographic location. There are a number of popular database programs, such as dBASE IV, that assist in the retrieval and management of such information in electronic form. The TNT products also handle databases and use specific terminology for the components that comprise a database. A database in the TNT products can be a main level object or a subobject of a raster, vector, CAD, or TIN object. The object generally defines the “unifying theme” (for example, the soil type polygons for the Crow Butte area). A database is organized into tables, which contain records that store attribute values for an individual example in one or more fields. (See also: external database, field, foreign key, internal database, primary key, record, table.) database query: The database tables attached to vector/CAD objects can be queried to reveal those elements that meet the criteria specified in the query and drawing styles can be assigned in accordance with query results. Database query can be used to select vector/CAD elements for display and assign their drawing styles. data mask: A processing barrier that only allows data values in a chosen range to pass. You might choose a data mask to block all values outside a selected color range, eliminating all image features except those of the color you want to use in a process. You can also use a mask to select a processing area from a larger scene. The mask blocks off the parts that you want to exclude from the current analysis. DataTip: A DataTip contains a raster cell value or element information for vector, CAD, or TIN object. For all objects except raster objects, you can designate the database table for use as a DataTip. Place the cursor on the cell or element for which you want to see a DataTip and wait briefly. DataTips operate in a manner similar to ToolTips. The DataTip with the pertinent value or information appears adjacent to the cell or element. In TNTmips, a virtual field can be used to produce a multiline DataTip for a single vector, CAD, or TIN object. Such DataTips present information from multiple fields in one or more database tables. datum: A mathematical description of a smooth surface that closely fits the mean sea-level surface for an area of interest, which provides an imaginary, perfectly flat horizontal surface for use as a map base with x,y coordinate measurements. A datum is derived from a chosen ellipsoid, and provides the surface to which a cartographer refers ground control measurements. Maps of large extent must use consistent parameters for ellipsoid and datum to insure consistency between the map projection and ground control. (Map Projections Used by the U. S. Geological Survey, Geological Survey Bulletin 1532, Second Edition, U. S. Government Printing Office, Washington, D.C., 1982, pp. 13-15). (See also: ellipsoid.) daughter object: A completely independent project file object that may be treated by TNTmips as subordinately related to some other object. For example, objects attached by HyperIndex® to some other object are called its daughters and the object used for the primary index layer is called the parent. (See also: HyperIndex, index area, parent object, stack) decibel rasters: Radar images in which the raster cell values are presented as log scale values based on the power of 2. Users can choose to generate decibel raster objects in addition to raster objects with linear cell values when they import JPL AIRSAR and TOPSAR radar formats. decision rule: The criterion used to assign cells to a prototype feature in TNTmips feature mapping. Cells in the image are tested against the decision rule, and those that match are highlighted as prototypes. You select the desired decision rule when setting up the raster objects to be analyzed by feature mapping. A simple decision rule would be to compare the three color values of each cell on the display to three color values known to occur in the target feature. DCW: Digital Chart of the World was the first digital 1:1,000,000 map of the world in VPF format. This data can be downloaded from the NGA website. This original product has been replaced by the more detailed VMap0 and VMap1 data sets, which are also available for download from NGA. defaults: The start-up settings for a system or an individual process. In TNTmips the defaults are usually automatically set to be the most probable value desired if the process is to be repeated either immediately or at some indefinite future date. Many TNTmips defaults are set to the last value, raster object, position, or other parameter used. Some defaults are always reset to a selected condition, regardless of the last choice, in order to prevent inadvertent destruction of valuable results and data sets. For example, the location of a new output raster object will not usually default to an existing object to avoid accidentally overwriting it. Well thought out defaults are one of the simplest and most easily incorporated forms of artificial intelligence that can exist in a system. degree or °: A unit of measurement equal to 1/360 of a circle. A degree of latitude on the earth’s surface is about 69 miles. A degree of longitude is about 69 miles at the equator and undefined at the poles, but any point on the surface rotates through a degree of longitude in about 4 minutes of time. (See also: arcsecond, minute.) Delaunay criterion: A condition that must be met when a TNTmips TIN object is computed. The technique used to generate the TIN object, known as Delaunay triangulation, produces a set of triangles that are as equi-angular as possible. All circumcircles of Delaunay triangles contain no points other than the three that define the triangle and its circumference. Satisfying the Delaunay criterion ensures that any point on the surface is as close as possible to one of the nodes, the number of long skinny triangles is minimized, each sample point is connected with two nearest neighbors to form a triangle, the triangulation solution is unique and independent of the order in which the points are processed, and the solution produced allows easy generation of Voronoi diagrams (Thiessen polygons) for the same set of input points. Voronoi diagrams are widely used in spatial analysis. DEM: Digital Elevation Model. (Also DTM, “Digital Terrain Model”). A computerized representation of an elevation surface. Specifically, a raster in which the value in each cell represents the surface elevation at that location in the scene. DEMs are USGS geographic elevation data distributed in raster form on open reel magnetic tapes. There are 2 basic types: 1) The DMA type created by the Defense Mapping Agency in both a fixed cell size and a 3 x 3 arcsecond cell size distributed in 1 x 1 degree files. 2) A newer format for those 7.5' USGS quadrangles that have been processed into 1 x 1 arcsecond elevation cells. demand: The number of something that uses a center in network analysis; for example, the number of students living along a road places a demand on a school (a center). Demand values are necessary before capacity limits can be meaningful. dendrogram: A tree diagram whose branches depict a hierarchical classification structure, showing the degree of relatedness of different classes. densification: Densification of vector lines adds vertices to a line to enforce a particular shape generated by splining. TIN densification is the process of adding nodes to a TIN object based on some criterion, such as highest deviation from a planar surface in an underlying DEM or correlation between a stereo pair of DEMs. (See also: TIN densification.) depression: (watershed analysis) A depression exists when the lowest elevation value within the watershed is lower than the lowest value of the cells that form the watershed boundary. Drainage is inward from the inside perimeter of the depression toward the lowest point. depressionless raster: An elevation raster created from the original elevation raster with all depressions filled. Such depressions are filled by assigning increased elevation values until a flow direction can be established without going uphill. The depressionless raster is attained when the number of depressions is reduced to zero. destripe: Procedure that removes systematic striping within an image. This striping typically occurs in an image generated by a multispectral scanner that sweeps multiple scan lines simultaneously. developable surface: A geometric form capable of being flattened without stretching or tearing, such as cylinder or a cone (both of which can be cut and laid out flat), and a plane (which is already a flat surface). device independent: Not constrained by idiosyncrasies of hardware environment. All processes in TNTmips function independently of the physical input, output, and display devices. Device independent software is also designed so that all of its procedures look and work the same way across a variety of hardware configurations. DGIS: Direct Graphics Interface Standard. diacritic: An accent mark added to a character to distinguish it in pronunciation or meaning from other uses of the same character. Common diacritics, for example, distinguish several versions of the Latin character “a:” á, à, â, ä, ã, and å. dialog box: A type of subwindow that opens to display a message, warning, processing message or application components that require the user’s input. The user must typically make some kind of decision and exit the dialog box before continuing with the process by pressing a button such as OK, Cancel, or Skip. diapir: An upfolded geologic structure, such as an anticline, in which mobile, plastic core material has broken through or pierced the more brittle overlying rock. digital: Information stored and processed with numerical digits, often in base 2. Digital information processing is constrained by the finite set of numbers a system uses, such that every data value is forced into its nearest representation. For example, a digital clock may only show hours, minutes and seconds, but not fractions of a second. At some point, every digital system faces the same kind of limit in accuracy. On the other hand, digital information is easy to copy, store, manipulate and reproduce dependably. (See also: analog.) Digital Elevation Model: See DEM. Digital Terrain Model: See DEM. digitize: Convert analog data into a digital form; also, more specifically, use an X-Y digitizing tablet to convert data to digital form. digitizer: A device that converts an analog signal or representation to a digital one. (See also: scanner, video digitizing board, X-Y digitizer.) digraphia: Use of two different scripts for the same language, such as Latin and Cyrillic for Serbo-Croatian, Devanagari and Arabic for Hindi-Urdu, and Pinyin and characters for Chinese. dimensionality: The number of coregistered images in a project file for one site. An image contained in one color composite raster has a dimensionality of one. An image contained in a three-raster RGB set has a dimensionality of three. A Landsat TM image map for a single date will have a dimensionality of up to seven. If elevation rasters, panchromatic rasters, and multi-date airphotos are added to the project file, the user will likely want to reduce the dimensionality of the image to simplify analysis and manipulation. (See also: dimensional reduction) dimensional reduction: Reducing the number of coregistered rasters in a project file to speed up their analysis. TNTmips’ dimensional reduction techniques include principal components and Kauth’s Tasseled Cap. dimmed selection: A menu selection that is not currently available as indicated by its grayed-out appearance. directory or sub-directory: In DOS, a directory is a logical, user-defined division of a storage device. For example, a user may divide a hard disk into several directories, with each directory used to store files that pertain to a certain task. One directory may contain programs and documents for word processing, another for spreadsheet analysis, and another for database manipulation. The DOS commands MD (make directory), CD (change directory), and RD (remove directory) are used to manipulate directories. Neweer operating systems use the word folder synonomously with directory. discrete values: Cell values of rasters that represent discrete data, such as categorical data, for which interpolated values have no meaning. disk drive: A mechanical component of a computer that allows data to be read from or written to a spinning magnetic or optical disk. displacement: The difference between the apparent x,y position of a feature in a raw photo and the feature’s true position. Displacement is caused by camera characteristics, tilt, nearness to the target scene, and variations in the elevation of the target terrain. display board or display card: An electronic circuit board installed in a microcomputer that translates the computer’s display data into signals for the monitor. display driver: The TNTmips system module that prepares image data for a particular manufacturer’s display board. display histogram: A graph showing the number of times a data value occurs in a raster display plotted against the range of possible values. For any RGB color the user selects, the TNTmips display histogram shows how may cells there are in the display for each intensity level of that color. display monitor or display screen: One of the two screens in a TNTmips system. The display monitor shows the image and works with the mouse. The other TNTmips screen is the text monitor, which works with the keyboard and displays menus and system information. dissolve: The removal of boundaries between polygons that have one or more specified attribute values in common. distance raster: An output raster created by certain classification methods which records the Euclidean distance between each cell and its assigned class center. Distances are represented as 32-bit floating point numbers. High distance values may identify cells which were not adequately classified using the chosen method and input parameters. dither pattern or dithering: An image processing technique that creates the visual illusion of continuous tones when an image is printed. The illusion of shading is obtained by the calculated placement of picture elements that usually can not be resolved by the human eye. The calculated placement of the picture elements is called the dither pattern and creates more colors and shades of color than would be printed otherwise on printers with fixed intensity, fixed size printels. dithered raster: A printer-ready 4-bit raster object in which each cell corresponds to one dot (printel) on the hardcopy output from the printer. DLG: Digital Line Graph. A USGS map format usually used to distribute topographic maps in vector form. DMA: 1) Defense Mapping Agency of the US Department of Defense. 2) Direct Memory Access. double precision: A high level of accuracy based on the possible number of significant digits that can be stored for each coordinate or raster cell value. DOS: Disk Operating System. DOS for personal computers is developed and marketed by IBM and Microsoft. It provides management utilities for the files and other resources of the microcomputer. dpi: Dots Per Inch. A measure of scanner, screen, and printing resolution. The more dots per inch, the more detail a device can process for a given area of page or display. On the other hand, the more dots per inch, the higher the demands on machine storage and processing (files get large and processing slows down). drag: To press and hold a mouse button while moving the mouse. drag bar: A window’s title bar. drape object: An object that takes its three-dimensional shape from a surface object that is lower in the layer list. Any object type that is usable in TNTmips can be used as a drape object. drawing order: The order in which layers are drawn during display. The object that is first in the drawing order will appear to be on the bottom when all layers are displayed. The order of objects in the layer list reflects the displayed appearance for a group with the background always at the bottom of the list. drawing style: The style used to render a screen or hardcopy representation of a vector or CAD element. The drawing style for point features includes size and whether unfilled, filled, or represented by a symbol. The drawing style for line elements includes line width and whether drawn in solid color or using a line pattern. The drawing style for polygon elements includes the border color and whether or not a polygon is filled. Your choice of single color filling or use of a transparent fill pattern and whether to draw the border if filled are also part of the drawing style. driver: A set of computer commands that control some input or output process for a particular type of hardware. Usually, drivers are written in assembly language. They tend to be small, very efficient translators of general program features into the specific communication protocol required by a particular manufacturer’s device. Everyone using word processing software should be familiar with the need to select and use the driver appropriate for the particular printer available. dropout: A missing piece of an image, or more generally, of a data stream. Dropouts can be caused by the improper use or function of a hardware device, by signal interference or disruption, or by other problems. A dropout in text transmission causes missing letters or words. A dropout in scanning can cause gaps in the image of a line. Scanning a fine line at too low a resolution or with too low a binary threshold is likely to cause dropouts in the resulting raster image of the line. DTM: Digital Terrain Model. Elevation data in a 3 x 3 arcsecond grid form or a similar rectilinear form created by the Defense Mapping Agency. DVD: Digital Versatile Disc. A 5" optical disc for video or data with greater storage capacity than a CD-ROM (currently 4.7 Gb). DXF: Data Exchange Format for storing vector or CAD data in ASCII or binary files, which can be used to interchange AutoCAD files with other CAD software.
easting: A rectangular (x,y) coordinate measurement of distance east from a north-south reference line, usually a meridian used as the axis of origin within a map zone or projection. False easting is an adjustment constant added to coordinate values to eliminate negative numbers. edge conditions: In agricultural row crop imagery, the biomass values for cells in the middle of a healthy row are high, while the thin plant fringes or bare soil between rows have low biomass values. Low biomass values along the edges of healthy rows are normal and are no cause for concern. But edges cannot be distinguished by value alone from the low biomass values of regions of insect or disease damage which must be identified and given special attention. EGA: Enhanced Graphics Adapter. A graphics subsystem capable of 64 colors and widely used in DOS-based microcomputers. The EGA was developed in 1984 to solve the poor resolution and limited color selections of the CGA. Most game software requires EGA, but the 64-color limit is unsuitable for serious image processing. (See also: CGA, VGA.) elgenvalues: Values used in the Hyperspectral Analysis and Principal Components processes. The dictionary definition of eigenvalue is: a scalar for which there exists a non-zero vector such that the scalar times the vector equals the value of the vector under a given linear transformation. eigenvectors: Used in Principal Components calculations and the Hyperspectral Analysis process, eigenvectors have value and direction. Eigenvectors are a mathematical rather than statistical entity. EISA: Extended Industry Standard Architecture. One of the standard bus architectures for microcomputers. (See also: bus.) ELAS: A public domain, first-generation mini- and microcomputer image processing system developed by NASA at the Stennis Space Center in Slidell, LA. elastic box: A rectangle displayed by TNTmips which can be moved or resized with the mouse. Elastic boxes are used to select areas on the display monitor in processes like measuring and drawing. elastic circle: A circle displayed by TNTmips which can be moved or resized with the mouse. Elastic circles are used to select circular areas on the display monitor in processes like measuring and drawing. elastic line: A line displayed by TNTmips which can be moved or resized with the mouse. Elastic lines are used to draw segments on the display monitor in processes like measuring and drawing. electromagnetic spectrum: “The entire spectrum, considered as a continuum, of all kinds of electric, magnetic, and visible radiation, from gamma rays having a wavelength of 0.001 angstrom to long waves having a wavelength of more than 1 million km” (Random House). Remote sensing devices typically record electromagnetic bands in the region of optical light and may include the near infrared. (See also: spectral band) electronic atlas: A HyperIndex created from maps, photos and airphotos, airvideo, and database links. The electronic equivalent of a printed atlas. element: (CAD) Any defined shape in a CAD object. These include arc, arc wedge, arc chord, box, circle, elliptical arc wedge, elliptical arc chord, ellipse, elliptical arc, line, point, polygon, and text elements. A block inserted into another block also acts as an element at its insertion site. Unlike vector elements, individual CAD elements retain their original shape regardless of what other elements are added and where they are placed. element: (vector) A vector object is made up of three different types of elements: 1) points, which are single coordinate pairs (or triplets) that define a point (such as a well); 2) lines, which are curvilinear strings of coordinates which define a curved line (such as a stream) and which have nodes at the ends and intersections of lines; and, 3) polygons, which are collections of lines which inscribe an area (such as a lake). ellipsoid: An ellipse rotated about its shorter axis. In the context of map projections, an ellipsoid is a geometric reference surface that closely approximates the geoid. Since the geoid (that depicts the earth) is an irregular spheroid characterized by polar flattening (or ellipticity), many methods have been developed to describe its ellipsoidal deviations. Cartographers have a selection of ellipsoids from which to choose; most of which have “best-fit” properties for certain portions of the globe. In 1924, an International ellipsoid was defined which described the earth ellipsoid as a flattening of 1 part in 297. Historically, ellipsoids were derived from careful surface measurements. More recently, satellite data has been used to construct ellipsoid models that relate coordinate measurements to the earth’s center of mass. A few common standards: GRS 1980 (North America), WGS 72 (NASA/satellite), Australian (Australia), Krasovsky (Soviet Union), Clarke-1880 (Africa), Clarke-1886 (North America, Philippines), Airy (Great Britain), Bessel (Central Europe, Chile, Indonesia), Everest (India, Burma, Pakistan, Afghan, Thailand, and other southern Asian countries), and International (most other areas). EO cartridge: See: erasable optical cartridge. EO drive: See: erasable optical drive. EOS: The Earth Observation Satellite used to study the earth as a system while tracking long-term, global changes. EOS is a NASA-sponsored mission. epidemiology: The study of the various factors influencing the occurrence, distribution, prevention, and control of disease, injury, and other health related events in a defined human population. epipolar: A condition of geometric coplanarity established between a pair of stereo images to give them the same relative orientation. Stereo images that have epipolar orientation can be used to derive a network of correlation points in preparation for DEM extraction. EPPL7: Environmental Planning and Programming Language. A raster-based GIS system developed and sold by the State of Minnesota. EPS: Encapsulated PostScript. equalized histogram: A histogram whose distribution has been mathematically adjusted so as to come as close as possible to having an equal number of cells of each data value. equator: The great circle that is equidistant from each of the earth’s poles and divides the earth into northern and southern hemispheres. Latitude is measured with reference to the equator. erasable optical cartridge or EO cartridge: A two-sided removable storage unit that typically holds between 300 and 500 megabytes per side. Data on EO cartridges can be erased so the cartridge can be updated or re-used. erasable optical drive or EO drive: A 5 1/4" high capacity storage device that uses removable double-sided cartridges which typically store between 300 and 500 megabytes per side. EO drives are similar to WORM drives, with the difference that EO cartridges can be erased and re-used, while data on WORM disks is permanent and cannot be erased. (See also: WORM drive.) ERDAS: Earth Resources Data Analysis System. A first-generation, raster-oriented microcomputer image processing and GIS system marketed by ERDAS, Inc. escape code: A code which controls the format of text output. SML supports a set of common escape codes: \t (tab), \b (backspace), \n (newline), \<carriage return> (line continuation: the “stitch” character), and \\ (the ‘\’ character). Ethernet: Ethernet is a local area network that uses a bus topology for reliable high speed communications in a limited geographic area, such as an office of university complex. euclidean distance: The shortest distance between two points in feature space, calculated using the Pythagorean theorem. exabyte, Ebyte, or EB: A computer unit of measurement for 260 (approximately) 1,000,000,000,000,000,000 bytes, 1,000,000,000,000,000 kilobytes, 1,000,000,000,000 megabytes, 1,000,000,000 gigabytes, 1,000,000 terabytes, or 1000 petabytes. (See also: bit, byte, gigabyte, kilobyte, megabyte, petabyte, terabyte, yottabyte, zettabyte) expansion slot: A socket for an optional circuit card on the main circuit board of a microcomputer (the motherboard). explicit destruction: When a user action has irreversible or negative consequences, the process requires the user to take explicit action and to confirm that intent by responding to an appropriate warning message, such as “Are you sure you want to delete selected items?” before destruction is performed. exporting vector or raster objects: Exporting an object from a TNTmips project file converts it to a format recognized by other image processing or GIS software. Color schemes; arc, node, and polygon structure; geographic calibration; and any other supporting data used in the target format is included. The completeness of the conversion is only limited by the extent to which MicroImages can decode the format from the developer’s information or determine it from sample files. expression: (in database queries) A line in a query that compares values. An expression evaluates to “true” (1) or “false” (0). Example: numlines < 3. It compares the numlines variable for the current node element with the number 3. The expression is true only if the value of numlines is less than three. Also, an expression can evaluate to a number (for example: 2*YIELD). If such an expression is used where true and false values are needed, 0 is treated as false, and anything else is treated as true. extents: The geographic extent of data specified by the minimum bounding rectangle. external database file: A database file that has been linked to a project file and is maintained as a separate file. An external database file may still be processed by your database programs. (See also: database object, internal database file.) external program: A program that is not part of TNTmips. It may be commercially produced or written by you. external raster: A raster file that has only been linked to a project file and is being maintained as a separate file. An external raster 1) is stored in a DOS file, 2) follows a very simple format, and 3) is not stored internally in a project file. To all TNTmips processes, this object still appears to be a part of a project file. However, external programs can modify it. extrema points: The highest and lowest points and flat areas locally as indicated by the elevation raster cell values. Extrema are change points determined by the comparison of each cell to the eight adjacent cells. A cell whose eight boundary cells are all lower than the cell is defined as a single local maximum. A cell whose eight boundary cells are all higher than the cell is defined as a single local minimum. Two or more adjacent cells with the same value whose boundary cells are all lower are defined as contiguous local maxima. Two or more adjacent cells with the same value whose boundary cells are all higher are defined as contiguous local minima. Two or more adjacent cells with the same value whose boundary cells also have the same value are defined as a flat area. false easting: An adjustment constant added to easting coordinate values to eliminate negative numbers. (See also: easting.) false northing: An adjustment constant added to northing coordinate values to eliminate negative numbers. (See also: northing.) far range: The region farthest from the aircraft in an image created by a synthetic aperture radar (SAR) sensor. FFT or Fast Fourier Transform: one of the procedures in raster filters. See also: Fourier Transform. feathering: One of the options available for handling cell values in the overlapping portions of the input objects in the Mosaic process. Two types of Feathering methods are available: Linear and Nonlinear. Each type uses a weighted average of corresponding input cells. The weighted average varies with distance from the image boundaries. The weighting coefficients for each image are zero at the boundary and increase inward to 1.0 at the feathering distance from the edge (feathering distance is specified by the user). feature: An area in an image that you locate and map in the TNTmips feature mapping process. A feature is a continuous area (it may have holes in it) that does not touch any other area of the same type. (When two features of the same type touch, they immediately become a single larger feature.) Features may represent anything the user chooses to isolate and identify, like ponds, lakes, agricultural fields, a biological entity in an NMR scan, or bones in a CAT scan. feature class: The identity of a feature supplied by a TNTmips user. A class is a set of all features of the same material. A class is named to identify the kind of material it contains (for instance “corn”). feature mapping: A TNTmips process for isolating, identifying, and typing areas in multivariable images. TNTmips can do most of the classification automatically when working with high-quality materials like satellite multispectral images. With more input from the user, the process may also successfully map features in images created from 35mm slides or noisy airvideo. feature space: The theoretical n-dimensional space occupied by n input raster objects. Each raster object represents one dimension, and its cell values represent positions along one of the orthogonal coordinate axes in feature space. The set of raster values belonging to a cell define a vector in feature space. feature type: The identity of a feature supplied by a TNTmips user. fiducial marks: (photogrammetry) Index marks, usually four, which are rigidly connected with the camera body and which form images on the film negative and usually define the principal point of the photograph. field: (database) One component in a database record. Fields report values (either qualitative or quantitative) for the individual represented by that record. For example, a database record in a table concerned with agricultural potential may contain fields that provide qualitative evaluations of a ground areas’ production potential for grain, legumes, or trees, while a database record in a table of polygon statistics may contain fields that report quantitative information such as the polygon’s area, boundary length, and centroid coordinates. (See also: database object, record, table.) field: (video) Background: The image you see on a TV screen is composed of a set of about 480 horizontal lines. The lines are projected in two passes of the signal beam. Each pass only projects every other line of the image: the odd lines in one pass, and the even lines in the next pass. One scan takes 1/60 of a second, so the whole picture (the frame) is refreshed every 1/30th of a second. A field contains every other line of the complete video image. The primary field contains the odd lines; the secondary field contains the even lines. field: (window) An area of a window that allows keyboard entry of text. field of view: Area visible from a viewers location. In the Viewshed process you can adjust the position of the viewpoint location in relation to the vertical plane of the surface object. figure-ground separation: Separation of the foreground (figure) from the background (ground) in an image. file: A stored collection of related material (programs and data) analogous to a physical file folder that is used to store a collection of papers on a particular subject. file format: A particular, pre-described layout pattern for data in a computer file so it may be used or acted upon by a program. A TNT project file has a complex format recognized only by the TNT family of products and by user programs designed and built with the TNTmips library. Similarly, a commercial database system uses only database files that follow its particular file format. fill color: A solid color used to fill a closed shaped in a vector or CAD object or an area defined by specified boundary colors in a raster object. fill pattern: The drawing pattern for the interior of a polygon for display or printing. TNTmips lets you create and assign fill patterns for raster (paint), vector, and CAD operations. A fill pattern can be as simple as a solid color, or as detailed as a repeated image of a duck or tree. Soil types can be represented by traditional color cross-hatching. Fill patterns can be designed from the 64 standard colors plus transparent (so the underlying image shows through). film recorder: An output device that works like a printer but produces slides or prints, usually on 35mm film. filtering: Clarifying detail, sharpening contrast, smoothing edges, and otherwise enhancing image quality. FIPS code: Federal Information Processing Standards code that identifies each state (2 digits) and county (3 digits). TIGER files are named by incorporating FIPS codes, e.g. TGR + 2-digit state FIPS code + 3-digit county FIPS code or TGR31109 for Lancaster County, Nebraska. flat: A raster cell that has the same cell value as its eight neighbor cells. Calculated from an elevation raster object, a raster object of flats provides a representation of locations with poorly defined drainage. flight path: The path taken by aircraft, satellite or other imaging sensor platform. The flight path controls the nadir as well as the area imaged. floppy disks, floppies, diskettes, or flexible disks: A thin, flexible magnetic disk for computer program and data files. Floppies are inserted into a computer’s floppy disk drive much like a cassette tape is loaded into a tape player. Floppy disks come in different sizes and capacities, and must be used in the right kind of drive and computer. Floppies are slower and hold less data than a hard disk. (See also: hard disk, RAM disk.) flow accumulation: In a raster-based analysis, the total number of cells, including non-neighboring cells, that drain into a selected cell. flow direction: In a raster-based watershed analysis, each cell is assumed to drain into one of its eight neighbors (left, right, up, down, plus the four diagonals). The flow direction of a cell is expressed in degrees: up=0, right=90, down=180, left=270; and the diagonals: 45, 135, 225, 315. flow path: The drainage path through a watershed that begins at any selected point (called the flow path “seed”) and runs to one of the outlets of the study site. flow path raster: A raster that indicates the flow path from one or more seed points to one of the outlets of the study site. flow path seed point: (watershed analysis) Any point selected to be the origin or highest point in a flow, or drainage, path. focal length: The distance from the lens at which parallel light rays are focused to a point. Focal length is essentially a measure of the “zoom” level of a camera lens. Longer focal lengths create a higher zoom level, capture a smaller area of the target scene, and introduce smaller displacement errors. 6-inch, 8.25-inch, and 12-inch focal lengths are common for aerial photography done by government surveying authorities in the United States. Focal length affects the geometry of the photo and must be provided as an input to computational orthoimage and DEM processes. folder: A folder contains a set of logically related objects in a Project File that have been organized so they can be accessed together. When you install TNTmips, all of its system modules are copied to a folder named TNT_WIN. A folder is equivalent to a DOS directory. (See also: nested folders.) font: A single set of glyphs (characters, symbols, numerals, and letters of both upper and lower case) of the same style (such as Times, Helvetica, or Schoolbook). Fonts can be stored and manipulated in computers as bitmapped or vector (outline, or stroke). Font sizes are specified in points. A 72-point font is one-inch high, from the highest ascender to the lowest descender in the set. A 12-point font is 1/6 inch high. (See also: bitmapped font, outline font, point size.) font set: A collection of one or more fonts that provide all the characters used by a particular language. foreign key: A primary key in one table that also exists in another table within the same database. A foreign key consists of one or more attributes that can uniquely identify a record in the table containing the primary key. The identification and designation of foreign keys are automatic. (See also: database, field, primary key.) form: See database form. format: The preparation of optical, floppy, or hard disk media; a tape cartridge; or other storage media with basic locational information so that the media can be used. Some manufacturers provide preformatted media for their specific devices, such as hard drives. Other generic media, such as floppy disks, are usually not formatted when purchased. Some media, usually those with a serial recording format, such as open reel tape, are automatically formatted as they are used. Fourier transform: A type of two-way frequency transform for identifying and removing unwanted spatial frequency components in an image. The Fourier process is normally used to identify and remove systematic noise “spikes,” such as regular lines that may have been introduced by a faulty image collection device. The process works as a two-way operation. First the forward transform creates a pair of intermediate raster objects that reveal abnormal data variability. After the values in those raster objects have been edited to remove the data spikes, the inverse transformation creates a raster object with the same image as the original, but with lines or other noise removed. This Fourier Transform process has somewhat the same smoothing effect as the low-frequency TNTmips image filtering process. frame: (video) A complete video image which consists of two interlaced fields. Odd lines of the frame are contained in the primary field which is alternated with the secondary field that contains the even lines. The primary field lasts 1/60 of a second in standard broadcast video. The secondary field follows in the next 1/60 of a second. The entire frame takes 1/30 of a second to display. There is a difference of 1/60 of a second between alternate lines in the image. frame: (window) The border around a window in TNTmips. The active window (where any typing or selecting of options will occur) is indicated by a highlighted or different colored frame. framegrabber and framegrabbing: Background: Composite video and US standard broadcasts repeat each field every 1/60 of a second. Two interlaced fields, each containing alternate lines of the image make up one video frame that lasts 1/30 of a second. A video framegrabber is a microcomputer interface board that accepts a video input signal and passes it to a color monitor. A program signals the video frame-grabber to both freeze and digitize one video frame. Digitizing a video frame may transform each picture element in the frame to a single byte in the board’s memory. More commonly, it simultaneously captures, digitizes, and stores the video’s separate red, green, and blue color values. Some framegrabbers can be set to grab only a single field to avoid the relative movement between a frame’s two fields. If the video comes from a camera that has high-speed electronic shuttering (like 1/1000 of a second), movement in the 1/30 of a second between the primary field and the secondary field causes saw-toothed edges on alternate lines in straight features like road edges, and vertical poles. As soon as the video is saved in the board memory (1/30 or 1/60 of a second), picture motion on the monitor freezes (even if the live video input continues) while the data in the board memory is converted into a display image. Then TNTmips reads the memory of the board and transfers the image into project file raster objects. Framegrabber boards should not be confused with video digitizing boards, which gradually sample and construct a digital representation of a still scene video image. Sampling video boards represent an older technology, but are still used for non-standard, higher resolution video sources. (See also: video digitizing board.) frequency transform: An operation that breaks down an image into its fundamental spatial frequency components for subsequent analysis or filtering. fuzzy C-means: An unsupervised classification or clustering process developed by Robert Cannon et al. and documented in: Robert L. Cannon, Jitendra V. Dave, James C. Bezdek, and Mohan M. Trivedi (1986) IEEE Transactions on Geoscience and Remote Sensing. GE-24(3):400–408. Segmentation of a Thematic Mapper Image Using the Fuzzy C-Means Clustering Algorithm. |
