Abstract
One major challenge, in geodesy, is the conversion of geodetic coordinates related to a geodetic datumto geodetic coordinates related to another datum, due to differences between datums in size and position. Essentially, there are two approaches, where the first, and most well known, is conversion via three-dimensional Cartesian coordinate space. The second, curvilinear transformation, is a direct transformation of latitude-longitude coordinates between two datums. The method proposed in this paper is named nine-parameter curvilinear transformation between datums and may be considered a new curvilinear transformation method. This method has good accuracy, since the difference between suggested transformation and seven-parameter transformation does not exceed 0.0015 arc sec. Moreover, it replaces several steps in seven-parameter transformation methods by one direct step.