Analyzing 2D Transforming The Global Coordinates Measured By GNSS To The Syrian Local Coordinates

The transformation of coordinates between the global coordinate system yield ellipsoid WGS84 (World Geodetic System 1984) and the local coordinate system yield ellipsoid Clark1880 in different regions of Syria, is the essential step in the effective use of GNSS (Global Navigation Satellite Systems) surveying techniques in Syria, and the transformation occurs with 3D transformation between one ellipsoid and another, or 2D transformation directly between two planar. The transformation must be understood, analyzed and tested. The research is about the accuracy of the 2D transformation in small area to give coordinates can be directly used in different surveying and engineering works, and about studying the common points number and their distribution effect on transformation accuracy, and conclude that the biggest effect on transformation accuracy is for the common points distribution.