Image Interpretation in Geology

Third Edition, by Steve Drury

Blackwell Science (U.S.) and Nelson Thornes (U.K.) have co-published Image Interpretation in Geology, a 304-page textbook by S A Drury.  Included with every copy is a CD-ROM containing TNTlite 6.4.

Since the first edition in 1987, Image Interpretation in Geology by Dr. Steven Drury has established itself as essential reading for earth science, environmental science and physical geography students studying the geological applications of remote sensing and image interpretation.

The new Third Edition of this book describes the fundamentals of remote data capture and image processing, their practical limitations, and new techniques such as digital radar imaging and hyperspectral data analysis. Geological applications such as mapping, mineral exploration, and geohazards are illustrated by numerous black-and-white photographs and a color plate section.

New to the Third Edition is a CD-ROM (combined Mac and PC format) which contains an image gallery (with accompanying spectacles for viewing in 3-D), exercises, and TNTlite 6.4. This software, a fully-functional version of MicroImages Inc?s TNTmips 6.4, encourages students to experience at first-hand the immense power of modern image processing and interpretation software, and allows lecturers to use a wide range of sample data and practical exercises to support their courses.

• Order from Blackwell Science:  http://www.blackwellpublishing.com/
• Order from www.nelsonthornes.com
• Order from Barnes & Noble: www.barnesandnoble.com

The first two editions of Image Interpretation in Geology won a wide readership among undergraduate and professional geologists, since 1987, but advances in the technology of remote sensing and its application demand some updating. In addition, there are always better ways of expressing concepts, so I have revised the style in most of the chapters. I have replaced several of the images with more instructive ones, and the further reading extends to 1999. Most important, I have added a CD-ROM that I hope will supplement and extend the usefulness of the book. In its new form, Image Interpretation in Geology transcends the original textbook to become potentially a complete, distance-learning course on remote sensing, image processing and digital mapping for geologists.

Thanks to MicroImages of Lincoln, Nebraska, the CD includes the students' version of their professional mapping and image processing system, TNTmips. This package, called TNTlite, is a unique example of highly sophisticated freeware, in that it is equally as functional as the professional version, limited only in terms of the maximum usable image size and with export from TNTmips format to other formats disabled. The CD includes both Windows and MacOS versions, so that almost everyone with access to a modern desktop or portable computer will be able to learn essential skills to a high level of sophistication. The package contains the full and comprehensive TNTmips reference manual and a series of Adobe Acrobat format, Getting Started tutorials, which cover all aspects of the system's functionality. Moreover, I have added 11 exercises that focus on all the geological applications of remote sensing covered by the text, which are based on a variety of image and nonimage data, mainly covering an area of stunning geology in the semiarid terrain of north-east Africa. They begin at an elementary level and progressively guide the user through the means whereby TNTlite manages, enhances and analyses digital image data that bear on geological problems. As well as the image data that the exercises use, many of the other digital images on the CD form a resource that instructors can use to create their own exercises and assignments, together with advice on how to import their own data in a TNTlite-compatible form. My choice of TNTlite as a teaching tool was solely because of Microlmages' unique policy of freely distributing fully functional software, and does not constitute an endorsement-readers must make their own judgment.

The CD-ROM includes the full set of stereoscopic pairs of aerial photographs that appear in Chapter 4. in the form of anaglyphs that can be viewed stereoptically using the viewing spectacles packed with the CD-ROM. This supplements the need to use a lens stereoscope to obtain full benefit from the text figures. Finally there is a collection of various types of image that contain important geological features.

Because there may be readers who wish to study the book simply as a textbook, and some who have no easy access to a computer, the text does not depend on the CD. At the end of each chapter is a brief guide to the relevant CD-ROM resources. Appendix C gives instructions for installing TNTlite, and also appears as Resources.rtf on the CD-ROM.

Remote sensing roughly means extending human sensory perception to distances greater than we can achieve unaided and to information that is far beyond our physiological capabilities. Vision is far and away our most powerful and flexible sense, and so the strict focus is on capturing information about the Earth's properties in the nearly continuous, two-dimensional fashion that is characteristic of images. This is possible only for those properties that control how Earth materials interact with electromagnetic radiation-not only visible light, but a spectrum that extends from gamma- to microwave radiation. Other attributes relating to natural variations in density, magnetic and electrical properties are detectable, but only in a discontinuous fashion-from point to point or along surveyed lines. The same holds for variations in chemistry, topographic elevation and the geometric structure of rocks, both at and beneath the surface, plus a host of other kinds of geological information. Although some of these attributes can be measured from a distance, the immediate results are not images. They are not excluded from the book, however, because there are means of recasting numbers distributed irregularly in two cartographic dimensions into the form of images. Visual perception is unsurpassed in extracting nuances from any kind of image, whatever its means of derivation. So, there is an overlap between remote sensing and more familiar means of gathering geoscientific information. Part of it is through images, and part through data analysis itself. One of the most important new tools is using computers to find patterns and correlations among far more layers of information than the human intellect can grasp. We deal as a matter of routine with spatial and to a lesser extent time dimensions, but a geological problem often involves tens of different dimensions. The vast bulk of the information is distributed in terms of geographical co-ordinates-it can be registered to maps. An extension from remote sensing is a sort of multidimensional aid to geological skills; a geographical information system (GIS).

Chapter I sets out to explain in relatively simple terms how matter and electromagnetic radiation interact. It is these interactions that laid the foundation for designing remote-sensing instruments, planning their use and interpreting the images that they generate. Although computers play an ever increasing role in geoscience, they will never replace the geologist. At the end of the day it is the eye and a mental kit-bag of skills, experience and intuition that generate ideas from perception of the real world. Chapter 2 makes some important points about how our visual system functions, and its power and limitations, both from a physiological standpoint and some of its more psychological aspects. This might seem strange in a geological text, but it is the key to matching the information contained within images to the make-up of the interpreter. The necessary background is completed in Chapter 3, which describes many of the instruments involved in generating images. This chapter also reviews the most important sources of images. The Internet is now the single most important means of discovering what information is available, and Appendix C lists sufficient, reliable URLs for beginning a search-many of the sites include Links to others in the same field, and of course the possible sources evolve continually.

Although remote sensing spans much of the electromagnetic spectrum, before 1970 the only public source of images was from aerial photography. The geological use of aerial photographs since the 1930s has left a priceless heritage of interpretative methods, on which remote sensing builds. Chapter 4 is the core of the book and concentrates on photogeological interpretation. Most of the images there are panchromatic photographs, often combined in stereopairs that can be viewed using a standard lens stereoscope (the CID contains all of these as anaglyphs, which you can view using the spectacles packed with it). Some are images derived from digital remote sensing systems, but are used for their content of information on geologically relevant landforms rather than their spectral features. Part of photogeology traditionally has been orientated to the extraction of geometric information and transfer of interpretations to maps; in other words to photogrammetry. Space prevented a proper treatment of this subject, other than aspects of photogrammetry that need to be carried out in the laboratory or the field, which are covered in Appendix A. There has been little advance in photogrammetry for geologists since the 1960s, and I have no hesitation in referring readers to older and more comprehensive texts on the subject, rather than to presume to improve on our forebears.

Remote sensing dramatically entered the geological scene with the launch of sensors aboard continuously orbiting, unmanned satellites in the 1970s. The technology had been available for 10 or more years, but locked

within the military intelligence community. Some of the first civilian systems that emerged with declassification were orientated to a broad and coarse view of meteorology and the oceans. The most revolutionizing aimed at visible and near-visible infrared parts of the spectrum, where vegetation is readily distinguished, and used a resolution less than 100 m to image small areas of the Earth's surface. The Landsat series, initiated in 1972, aimed at providing strategic economic information on the global cereal crop. This never fully materialized, but as well as many vegetation-orientated users, geologists seized on the new, wide and detailed view of landscape. The potential for complete, near-global cover in a standard form revitalized the ambition to extend geological mapping at scales better than 1 : 250 000 from 25% of the continents to the remainder, by using Landsat images as supersynoptic aerial photographs-they are more than just that.

Because the platforms that carried the sensors were unmanned and in quite high orbits, they had to transmit images in electronic form. Rather than using ordinary television methods, the decision was taken at an early stage to code and transmit the data digitally, In Chapter 5 you will grasp the enormous opportunities for 'tuning' digital images to human vision and extracting hidden information from them. It focuses on the spectral properties of materials in that part of the solar spectrum that the Earth's surface reflects. Appendix B complements that by a brief account of digital means of removing the blemishes and distortions that can affect many kinds of electronically captured data.

Conceptually more difficult to interpret are images that depend on the emission of thermal energy by the surface, and the strange interactions of artificial microwaves used in radar remote sensing. These form the topics of Chapters 6 and 7. Perhaps more so than systems operating at the familiar end of the spectrum, thermal and radar studies are attuned to geological phenomena, but there are relatively few geoscientists who are well versed in their intricacies, partly because most images from them derive from experimental airborne systems. The first decade of the 21st century promises to open new vistas with the deployment of such systems on satellites, and an early grasp of the possibilities will allow readers to take advantage of novel opportunities.

Geoscientists collect all manner of information relating to natural force fields, environmental geochemistry and exploration records, as well as lithological and structural data. A gravity determination, an analysis of soil, a borehole log or even a measurement of dip and strike at an outcrop are costly. In past decades, such data were gathered for a single purpose, perhaps an exploration programme, then set aside. Simple graphical expression of these variables rarely exploited their full content, and often treated them in isolation. Transforming spatially distributed data into image form, applying digital enhancement methods, registering many types of data to a common geographical base and then applying multivariate analysis techniques opens new vistas. Not only can the data be revitalized in later programmes, but GIS techniques permit a kind of information fusion that draws together many lines of evidence in solving problems or generating new ideas. Full and often unsuspected value can be squeezed from the records. Moreover, the fusion also helps bring the combined experience and different skills of several people to bear on problems; not any easy task otherwise, as many a manager will verify. This new and growing approach to information forms the topic of Chapter 8.

No course on geological remote sensing would be complete without an explicit guide to its practical applications. Ideally, the best option would be to use actual case histories, but the problem is to precis the best while extracting useful generalizations within set page limits. In Chapter 9, 1 have chosen to let the experts speak fully for themselves by referring to important case studies, and concentrate on some general principles of strategy and tactics. This covers several topics: landform studies, geological mapping, hydrocarbon, metal and water exploration, engineering applications and studies of natural hazards. They are set in the framework of conventional field surveys, but show how remote sensing can provide vital clues at critical stages.

Remote sensing aided by digital image processing is aesthetically pleasing, because all of us like colourful pictures. If we did not then it would be a pretty sterile

exercise, for it is stimulation of the visual cortex that draws us to find information and then interpret it. However, such sentiments cut little ice with exploration managers and referees of funding proposals. The key to their hearts is cost-effectiveness. A few figures can work wonders. Field mapping in remote areas costs between US$100-1000 per square kilometre, with an efficiency of between 1 and 10 square kilometres per day, depending on the level of detail. Preparing geological maps at the reconnaissance level using remote sensing costs from US$0.7-5 per square kilometre, and can run at efficiencies between 50 and 10 000 square kilometres per day, depending on whether airborne or satellite imagery is used and on the information content of the images. Although I must emphasize that remote sensing is no substitute for hitting rocks with hammers, the synoptic view and the access to invisible and rich spectral attributes of surface materials help orientate field work to the most critical areas. They also permit confident extrapolation from visited areas to more remote terrain that no longer needs direct attention. Information fusion through GlS methods brings every conceivable lever to bear on resolving problems and grasping novel opportunities.

Steve Drury
Cumbria, England

NOTE

Some technical terms and concepts appear in the Glossary.

The CD-ROM at the rear of the book contains resources aimed at extending and applying what you should have grasped from reading the text. 1 hope that it transforms Image Interpretation in Geology from a textbook supporting courses in geological remote sensing to a course in its own right, that will help professional geologists develop new practical skills through home study, and can support college instructors in enriching existing courses or setting up new ones for undergraduate geologists.

The central component uses a version of the professional Map and Image Processing System (TNTmips) software developed and marketed by MicroImages Inc. of Lincoln, Nebraska, USA. MicroImages are the only software developers in this field to offer a freeware version (TNTlite), which is fully functional. TNTlite differs from TNTmips only insofar as it limits images to a maximum size of 314 368 cells (e.g. 512 614, 1024 307 pixels), vector objects to 500 points, 1500 lines and 500 polygons, CAD objects to 500 elements, TIN objects to 1500 nodes and database objects to 1500 records per table, and has disabled export capabilities. [Note: export from TNTlite is enabled beginning with 2006:72] These limits, however, do not prevent results being printed, and TNTlite can be used for small research projects.

The inclusion of TNTlite in Image Interpretation in Geology does not imply any endorsement by either the publishers or myself.

On the CD are 11 Exercises linked to Image Interpretation in Geology, which are designed to allow users to master the skills associated with TNTlite processes. These skills are essential in all aspects of geological remote sensing, image interpretation and the production of digital maps to a publishable, professional standard. Each exercise uses data files specially prepared to be compatible with TNTlite. The CD also contains Microlmages' own tutorials and supporting data files, as a series of 54 Getting Started booklets in Adobe Acrobat format (the latest version of Acrobat Reader is on the CD too). Those resources cover aspects of remote-sensing and other geospatial applications (land use, urban and environmental) that will be broadly useful to Earth scientists. The full TNTmips Reference Manual, which provides more detailed guidance, is also on the CD-ROM.

Randy Smith, PhD of MicoImages Inc and Margaret Andrews of the Open University helped enormously in getting the Exercises working, technically and as teaching material.

Two other kinds of resource reside in separate folders within the Image Interpretation in Geology directory (Imint) on the CD. One folder contains anaglyph versions of all the stereopair figures in Chapter 4. You can view them while reading Chapter 4 by using the redblue spectacles packed with the CD, either in a graphics package, such as Adobe PhotoShop or MS Photo Editor, or in TNTlite after importing these JPEG files to MicroImages format (see later). Other folders contain a collection of different kinds of images, which illustrate various geological themes and types of imagery, and have appended brief descriptions. You should view these using a Web browser because the images are linked to text using HTML-i.e. the compressed images are in a separate sub-folder and therefore accessible by themselves. Many of the images in the collection have sizes that are compatible with TNTlite, so they can be imported as a means of adding interactive, digital interpretation to Exercise 9. They are 24-bit RGB JPEGs and so are limited to three channels. That somewhat limits their use with the other exercises, but the JPEGs can be unpacked to three 8-bit components within TNTlite, for experiments with contrast stretching, some ratioing and filtering.

Contents of the CD-ROM

The CD contains several folders or directories, most of which relate to TNTlite.

TNTIite resources

There are many folders associated with the TNTlite resources on the CD, some of which are copied automatically when you install TNTlite on your hard disk, and others that you have the option to install or use from the CD. The most relevant of those which you can choose to use from the CD are:

Data contains data compatible with TNTlite (in Data\Litedata) that are formatted as Microlmages project files (*.rvc), each of which contain several data objects of various kinds. Microlmages' own tutorial exercises (documented in the Getting Started Acrobat format *.pdf files) use them.

Getstart contains illustrated Adobe Acrobat documents (*.Pdf files) for each of the MicroImages Getting Started tutorials. 

Folder Acroread contains the latest Adobe Acrobat Reader software that automatically runs from the CD when you open an Acrobat document from Getstart by double-clicking on a *.pdf file. If you opted to install the Getting Started documents on your hard disk along with TNTlite (see Installing TNTlite below) you can access them from the Help option associated with each TNTlite process window as you are working, or at any time from the main TNTlite menu (Display/Getting Started).

Refman contains the full, 2500 page TNTmips Reference Manual as HTML files and linked GIF images (in subfolders Ci and Li). You can start this from Netscape or Internet Explorer by using File/Open Page or File/Open, respectively, selecting the CD (e.g. D:), then D:/Refman/Html and double clicking on Toc.htm (table of contents). If you opted to install the Reference Manual on your hard disk along with TNTlite (see Installing TNTlite below) you can access relevant parts of the manual from the Help option associated with each TNTlite process window as you are working, or at any time from the main TNTlite menu (Display/Reference Manual). The manual is comprehensive, and you may find it easier first to refer to the Getting Started document appropriate to a process which you find difficult, and going to the Reference Manual if you need details about how a process works.

If you have plenty of space on your hard disk, you will find it simplest to install all these folders, as well as the TNTlite software, on your hard disk (see Installing TNTlite, below).

Image Interpretation in Geology resources

The folder Imint is where you will find all the material explicitly connected with Image Interpretation in Geology. Within it are three folders:

Exercise This contains folders for the text and the data that you will use in the TNTlite geological exercises.

Anagly1 This contains all the anaglyph versions of the stereopairs in Chapter 4. You can easily access them from the CD using either TNTlite or a graphics package, but copy the folder onto your hard disk if you have plenty of space.

Anagly2 and Imagery. These contain selections of instructive images from various sources and linked HTML text-more anaglyphs and different types of images, respectively. Again, you can opt either to access them from the CD or copy the folder onto your hard disk.

If you have plenty of space on your hard disk, you will find it simplest to install all these folders on your hard disk (see Installing Resources, below).

Installing resources

Minimum requirements

TNTlite

Hard-disk space: At least 80 Mb for the TNTlite software. Getting Started and Reference Manual folders take up 60 and 35 Mb, respectively, plus an additional 150 Mb if you wish to install all the Getting Started data sets, but you can access them from the CD if your hard-disk space is limited.
CD-drive: Obviously!
Processor: PCs-Pentium III, Pentium 11, Pentium Pro, Pentium or 486 computer (or compatible); MacIntoshPower Mac.
Operating system: PCs-Windows 95/98/2000; Maclntosh-MacOS 8.0 (version 8.6 or higher is recommended); LINUX
Random access memory (RAM) At least 16 Mb (32 Mb recommended, especially for MacIntosh). For Macs, virtual memory must be set to at least twice that of RAM.
Display: Minimum area of 640 X 480 pixels displaying 256 colours (recommended minimum for Image Interpretation in Geology exercises is 1024 X 768 pixels and 16-bit colour).
HTML browser: Netscape Communicator or Internet Explorer.
Adobe Acrobat Reader (the latest version is in D:/Acroread/Win1Win95nt).

IIG Resources

Sufficient hard-disk space for the data files associated with the Image Interpretation in Geology Exercises. They take up about 140 Mb (including about 100 Mb for the hyperspectral data) and text files for the Exercises (less than one megabyte). If you are short of space, then you can access the folder (Imint/Exercise /Data /Cuprite) containing hyperspectral data from the CD-ROM. You must in any event load all the other data associated with the Exercises (Areal.rvc etc. in Imint /Exercise/ Data) onto your hard disk, because you will be saving results into these files. Images and HTML files that illustrate the text of Image Interpretation in Geology occupy about 30 Mb.

A graphics package, such as Adobe PhotoShop or MS Photo Editor;

A Web browser, such as Internet Explorer or Netscape Communicator (as high a version as you can get), as all the Exercises are in HTML. If you do not have a browser, or the HTML versions do not run properly, you will also find copies of the exercises in Rich Text Format (RTF, *.rtf) which should be readable in their original format using any word processor less than 10 years old (NOT Notepad or other text-only packages).

Installation

PC users: autorun

If your system supports Autorun CDs, a few seconds after loading the CD a "splash" window will appear on screen. This has 6 buttons:
IIG Menu...
Install IIG Resources...
Install TNTlite...
Run TNTlite...
Browse...
Exit

IIG Menu Clicking on this button loads an HTML menu page into your default browser. This provides links to all the IIG Resources on the CD (in folder Imint), and allows you to use the resources-including the Exercises and data that relate to the TNTlite geospatial analysis software-directly from the CD.

Install IIG Resources Clicking on this button immediately copies all the IIG resources in the folder D: / Imint from the CD to your hard drive, using the DOS utility xcopy. The path to the new folder containing the IIG resources will be C:/Imint, i.e. it will be a top-level folder on your hard disk.

Install TNTlite Clicking on this button starts the TNTlite installation procedure. You will first have to confirm that you wish to Continue with installation (ignore the instruction to attach the software licence key). There now follow some informative windows covering system requirements that you have already read in the previous section. The next important window deals with Setup Options, of which you can select only one at a time. Select Install/Setup the TNTlite version of TNTmips and press Continue. Setup offers you the option of taking the default destination for TNTlitePath: C:\Tnt-win--or choosing another. Accept the default, when Setup installs the software and shows you progress. When done, the installation procedure returns to Setup Options window. Click in the window once, and you can decide whether or not to install the Reference Manual, the Getting Started booklets and the Sample Data associated with them.

Run TNTlite Clicking on this button launches the TNTlite software, provided that you have already installed it in C:/Tnt-win. If you have not done this, nothing happens (TNTlite will not run from the CD). The button is provided so that you can use resources and data on the CD if you chose not to copy them to your hard disk because of space problems.

Browse Clicking on this button opens a window showing the contents of the CD. By double clicking on a particular folder, you will see a new window showing its contents and so on. You can open RTF, HTML and PDF files from here, by double-clicking on their icons, which will launch your default word processor, browser or Adobe Acrobat Reader. This is particularly useful for the TNTlite Getting Started booklets (in folder D:/Getstart), the TNTlite Reference Manual (in folder D:/Refman/html) or the IIG Resources (various folders in D:/Imint), if you have decided not to copy them to your hard disk.

Note: Each time that you need to use the "splash" buttons, you should eject the CD tray and then re-insert it.

PC users: manual

If for some reason Autorun does not display the "splash", you will need to perform the above manually, using Windows Explorer, as follows:

IIG Menu Display the contents of D:/Imint, and double click on Menu.htm.
Install IIG Resources Copy DdIrnint-and all its contents to your hard drive C:
Install TNTlite Double click on Setup.exe in D:, or use Start/Run with the command line D:\setup.exe.

Note: Unlike many software packages, installing TNTlite does not create strangely named files and stealthily place them in some other hard-disk folder, where you can never find them. So there is no need to carefully uninstall the software. If you want temporarily to create space for something else, simply delete the whole C:\TNT-WIN folder, and re-install TNTlite when you need to.

Run TNTlite Installing TNTlite will automatically add a line to your Start Up menu (Start/Programs) from which you can run TNTlite 6.4. But see Tips below.

Browse You can browse the CD, as above, directly from My Computer or Windows Explorer.

Useful tips

Using the Resources can be made easier if you create Shortcuts to several things.

TNTlite When you have completed the installation you will see a small window (Free TNTlite products) with several icons. Left-hold-drag the icon labelled TNTmips 6.4 onto your desktop. Double-clicking on the shortcut will launch TNTlite.

If you have installed the Reference Manual on your hard disk, you can create a shortcut to the Table of Contents document on your desktop, so that you can study the manual without having to start TNTlite. Go to C:/Tnt - win/Refman/Html in Windows Explorer and right-click on Toc.htm. Select Create Shortcut from the pull-down menu, and then click-hold-drag the shortcut file onto your desktop from Windows Explorer. Doubleclicking on the shortcut will open the Table of Contents in your default browser, and you can select links to all the features of TNTlite.

IIG Resources If you have copied all the Resources to your hard disk, go to C:/Imint and right click on Menu.htm. Select Create Shortcut from the pull-down menu, and then click-hold-drag the shortcut file onto your desktop from Windows Explorer. Double-clicking on the shortcut will open the IIG menu in your default browser, and you can select links to all the resources associated with the book.

PowerMac users

On a PowerMac Autorun will not function. Instead you will see the contents of the CD in a window when you open the CD icon from the desktop.

Install TNTlite Double click on the Installer icon. The next window allows you to select the License Options, so select Install TNTlite ... and press OK Check TNTmips 6.4 for PowerMac, (if you wish to install the Reference Manual check the Reference Manual HTML option) then press Install. TNTlite now loads into a folder on the hard drive automatically named TNT Products 6.4.

Note: Unlike many software packages, installing TNTlite does not create strangely named files and stealthily place them in some other hard-disk folder, where you can never find them. So there is no need to carefully uninstall the software. If you want temporarily to create space for something else, simply delete the whole TNT Products 6.4 folder, and re-install TNT'lite when you need to. Because files copied from the CD may be locked, you will need to hold down the Alt key when selecting the Empty Wastebasket option in order to completely delete them from the hard drive. This also applies if you wish to empty the Imint folder from the wastebasket (see below).

Run TNTlite Open the TNT Products folder and double click on the TNTmips icon. TNT displays a MicroImages logo screen and then opens a full screen window named MicroImages X Window System (MI/X). All TNT processes take place within this unique X Server. Treat the Micro-Images X Window System as a simple background window. Any time during a TNT session, you can use the normal Macintosh techniques (such as the Apple menu or the Application menu) to jump from MI/X back to the Mac desktop. TNTlite should appear thereafter as a recently used application in the Apple pull-down.

Install IIG Resources Copy the Imint folder to your hard disk. For ease of access to the IIG Resources you will need to launch Menu.htm from this folder. It will appear as a recently opened document in the Apple pull-down menu thereafter.

Working with the lIG resources

The whole package of resources that relate to Image Interpretation in Geology is designed for access using a browser (Netscape or Internet Explorer) from the HTML file Menu.htm in the Imint folder on your hard disk (or as a desktop shortcut on a PC), which links to all the resources, except for TNTlite. You need to launch TNTlite separately, either from Start/Programs or a desktop shortcut (PC), or using the recent applications and documents in the Apple menu (PowerMac).

TNTlite uses MI /X, MicrolImages' X-server that operates within Windows or MacOS (it is similar in some respects to the UNIX windowing system). The X window that opens, and within which all TNTlite windows appear, when you launch TNTlite, has one problem: you cannot easily resize it. That does not mean that TNTmips and other Windows or Mac software will not work at the same time. The X Window merely hides them. That is no great problem, as both PCs and PowerMacs have means whereby you can bring other windows to the front of the display-the Auto Hide and On Top functions for the Windows and MS Office Task Bars, in the case of a PC. However, every time you click inside the X Window the others hide again. You will need to find ways to shift from one set of windows to the other. A crude option is to minimize the X Window-the '-' box at top right, but it is better to bring Windows or MacOS windows to the front when you need to, using the Task Bar in the first case and toggling the X-window using the Finder Icon on a Mac. So that you can view both the text for the Exercises and TNTlite windows, the larger the display area for which you have set your monitor, the more you will be able to see when reading instructions. An area of 1024 x 768 pixels is OK, but 1280 x 1024 is obviously better.

Once you begin the TIG Exercises, resize the window that you use to view the text to reveal as much as possible of the TNTlite windows. HTML files automatically fit the width of a browser window, so will pose no problems. If you view the RTF format text files for the Exercises in a word-processor window, you may find that some of the text is hidden, depending on your software. Using the View/Online Layout option in recent versions of MS Word automatically wraps text to the width that you choose. If this is not possible, then you will need to reset the line length for the text files to the width of your resized window.

Getting help

Like all image processing and desk-top mapping packages, TNTlite is complex and completing the exercises involves your mastering many different windows. It is possible to get stuck or lost! The Getting Started booklets are very useful in resolving common problems, as is the Reference Manual. Two booklets entitled Getting Started: Displaying Geospatial Data and Getting Started: Navigating are particularly useful in helping you learn to navigate around in TNTlite and display your results. I have tried to follow MicroImages' style in the JIG exercises, but to save space they do not repeat the basic TNTlite XWindows operations. It is essential that you begin with Exercise 1, which explains the most important, basic aspects of that style of operation. There are reminders in later exercises of these basics, but not often, so as to build up your skills in as short a space as possible. So, you can resolve any difficulties as you mount the learning 'ramp' if you return briefly to the earlier exercises to refresh your memory.

If you find any parts of the exercises difficult to follow, even after looking for general guidance in the Getting Started booklets, please contact me via Blackwell Science (but do persevere for longer than a few moments before writing). That will also help me to refine the instructions for a revised version of the CD. I will NOT answer questions relating to operating systems or hardware, expecting you to be thoroughly familiar with your own computer or having direct access to someone who is.

MicroImages is a commercial company, with primary duty to those clients who have purchased the professional version of TNTmips. MicroImages software support engineers give preference to those clients. However, as time allows, they will respond sympathetically to queries from TNTlite users. Use support@micoimages.com for e-mail: and #1-402-477-9559 for fax enquiries (please do not phone) to contact MicroImages Software Support.

MicroIrnages continually develops its products, generally releasing new versions twice a year. Anyone can obtain upgrades for TNTlite either by downloading from the Web (http://www.microimages.com) or requesting a CD (MicroImages may impose a small charge to cover shipping the CD) from:

MicroImages, Inc.
11th Floor 206 South 13th Street
Lincoln, NE 68508-2010 USA
Fax:#1-402-477-9559 e-mail: info@microimages.com

©MicroImages, Inc. 2013 Published in the United States of America
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