1 AN ANALYTICAL APPROACH TO THE DISTORTION CHARACTERISTICS OF GINZBURG’S POLYCONIC

Some map projections are defined by table values rather than mathematical equations. The most popular and famous one in this category is the Robinson Projection. The Ginzburg projections, which were developed and applied in the former Soviet Union, are among the other table-based world projections. A computational method is required in order to efficiently use this kind of projections in Geographic Information Systems (GIS) and similar environments. Function matching for these projections can be carried out for a numerical forward and inverse transformation. Matched functions also allow the determination of the projection distortions easily. In this study, polynomials are applied to derive an analytical expression from an array of tabular coordinates. The tests are carried out for four table-based polyconic projections, The Ginzburg IV, V, VI, and 1966. The distortion characteristics are searched with the partial derivatives obtained by numerical approximation