DEVELOPMENT OF PC BASED SOFTWARE FOR SOME SELECTED MAP PROJECTION SYSTEMS INCLUDING INTER CONVERSION

Abstract

'Precise representation of the surface of earth on a two dimensional surface has always posed a. problem and hence has been a subject of investigation giving rise to a. number of map projection systems. Since the shape of the earth is spheroidal, the presentation of whole or part of globe on paper has not been possible to satisfy the shape, size and direction requirements truety. Attempts to maintain one of these truely may cause intolerable distortion in the other parameters. No single map projection has therefore been universally adopted for different types of mapping jobs. This is because of the fact that not only there is no such ideal multipurpose projection system bTJ.t a.I So more of ten than not, national considerations override the international one. The important map projection system in common use world wide are Polyconic and Universal Transverse Mercator (UTM). While Polyconic is the map projection system adopted by India., most of the western countries have adopted UTM as the projection system for mapping. A new map projection system called Space Oblique Mercator (SOM) has been considered best projection system for satellite imageries. To enable the cartographers, surveyors and engineers to carry out tedious computations of these systems and transformation of one to other systems a.n interactive software package. has been developed in this dissertation. This package has following capabit iisies (a.) It converts geographic coordinates to grid coordinates of Polyconic, UTM, Plane Orthographic and SOM projection systems. (h) It can inter-convert grid, coordinates from one projection system to other above mentioned map projection systems. (c) Grid coordinate in any map projection can be computed at required interval. Further this grid can be plotted at the desired scale. Also the control points and other points of interest are plotted on the man sheet by computer. It is hoped that this package will be very hQipfuI to engineers and cartographers in solving some of the mapping problems.