ABSTRACT
This chapter illustrates some of the computer programs and subroutines necessary to various aspects of mapping. First subroutines are given which accomplish the direct transformation for 18 of the most useful projection schemes. This is followed by subroutines for a selection of inverse transformations. The chapter introduces a program which evaluates single points or generates an entire grid for the direct transformation. This program calls up the mapping subroutines selected by the user. The program also carries out the inverse transformation for selected projections. The chapter then presents a program which applies to state plane coordinates. Direct and inverse transformations are included for both the transverse Mercator and Lambert conformal projections. Following this is a brief program which generates coordinates in the universal transverse Mercator (UTM) grid system. Since a map is a visual experience, rather than simply a set of numbers, the chapter discusses some consideration to the computer display of mapping grids and positions.
