Evaluation of UTM and LCC2SP Map Projections (Case Study: Iran)

Six conformal map projections, including UTM zones 38 to 41, LCC2SP and obsolete TM, are mostly used in Iran. Since some provinces extends to more than one zone, optimum selection of a map projection that lays minimum distortions is the most challenging problem in several mapping organizations of Iran. Choosing LCC2SP map projection is the usual approach adopted by mapping organizations to overcome the problem. Nevertheless, UTM map projection has lesser distortion in some provinces as our results illustrate. The aim of this paper is to recognize the optimal map projection with minimum distortion from mentioned map projections. Therefore, the amount of distortion is computed in different areas via the scale factor formula of each map projection. Finally, the map projection, with minimum distortion in the whole area of a province, is introduced as an optimal map projection for that province. For instance, if Fars province, which lies in UTM zones 39 and 40, is mapped by UTM 39, it will be represented with minimum distortion. Using optimal map projection for each province results in the reduction of the distortion and consequently, the produced map will be more accurate.