The use of GPS readings has led to a real revolution in Geodesic sciences and their applications. Now, the possibility of replacing the conventional methods used in measuring elevations by using GPS technology which is a good method to get the 3D points providing that the GPS measures the helical elevations. In order to measure the Physically important elevations such as the ortho-metric elevation, there must be an accurate specimen that gives the Geoids of the helix ( Geoids separation ) .In some parts of the world ( as in the case of our study ), there are only universal Ganoids .Those ganoids are calculated as series to reach a certain defined degree. The difference in the elevation ref. surfaces and the surface of the global geoids affects the optimized elevation of the GPS, but if we deal in this paper with the deviations in elevations, there will be no problem . The importance of this paper starts here , as we can get the possibility of taking the deviations in elevations by using The GPS tech that does not exceed /500m/ distance along with improving the results by using EGM2008 model. The results of the deviations in elevation taken by GPS, the Universal Geoids specimen /EGM 2008 / the direct engineering and triangular settlements, will be compared so that we reach some recommendations that increase accuracy in work and save time and efforts.