2.1. Introduction |
A Digital Terrain Model is made from a job done with 3D and 2D drawing elements having elevation (contour lines, 3D lines, etc.), or alternatively with field data represented by points. These points, conveniently "joined together", make up what is called a scatter plot. The points are represented by their X, Y, Z coordinates and usually by an ordinal number and an associated code. These data organized in lines and columns with defined separators form a point data file. This application also allows one to modify the scatter plot by means of a set of tools that are described in this section.