Vector Combinations

V5.40 -- July 1996

The Vector Combination process in TNTmips (Prepare / Vector / Combine) provides nine different operations for geographic combination of vector objects. These operations use both logical and mathematical combinations and include:

  • Add
  • Subtract
  • Logical-And
  • Logical-Or
  • Logical-Exclusive-Or
  • Extract
  • Extract and Clip
  • Extract and Add Boundary
  • Inverse Extract

    The Vector Combine operations use a Source vector object and an Operator vector object. You can select elements for combination from both the Source and Operator using key field attributes, database queries, or on-screen mouse selections. In the illustration here, five highlighted polygons have been chosen from the Operator with the mouse.

    Soilvect.gif - 37.1 K Operator.gif - 6.0 K

    Source Vector Object

    Operator Vector Object

    The Extract operation identifies all elements in the Source object either completely or partially included in the Operator region. All such elements are included in the result without any clipping.

    Vectex2.gif - 12.0 K

    Extract

    The Extract and Clip operation finds the elements in the Source object that overlap the region defined by the Operator, and clips those elements at the boundary of the Operator.

     

    Vectex1.gif - 6.2 K

    Extract and Clip

    Vector combinations are used in many applications and are among the basic tools of GIS analysis.