A Comparison of Orthometric Heights Calculated from (GPS/Leveling) and (EGM08) Methods Based–GIS

Interest in the study of global gravitational models has increased recently all over world because it is necessary for height datum transformations. Today International Center Global Earth Models (ICGEM) provides largest collection produced through data from satellite's missions CHAMP, GRACE, and GOCE ... Etc. To allow easy access internet with its more intelligent technologies, one Gravity Organization's services. While Positioning System (GPS) become most preferred technologies engineering surveying, a major dilemma GPS survey lies oval-based elevations. At same time, orthometric heights are commonly used field. Therefore, to convert measured by satellites assigned elliptical surface into supported geoid (mean sea level) an accurate geodetic model. The differences between measurement DGPS/leveling (obtained 57 points area) increasingly professionals geographical information systems(GIS). However, local determination Geoid better accuracy DGPS. This paper aims introduce modern technique determining elevation, avoiding cumbersome time-consuming spirit leveling operations. Fast vertical positioning can be obtained using DGPS models. Root Mean Square Error (RMSE) ± 0.19 m high precision derived EGM08; thus, describes Earth's field detail.