![]() ![]() GNSS observations of four different points were processed with Compass post processing software using the various, old sets and the unified transformation parameters to obtain the positions of the points. Consequently, this paper compares the positions computed from DGPS/GNSS observations using the various, old sets and the unified transformation parameters. Since the positions of reasonable number of points had been computed using these old sets of transformation parameters before the new/unified ones were derived and promulgated, there is need to verify which of the positions computed with the old sets of transformation parameters agree with the positions computed with the new/unified ones. Prior to the derivation of the new/unified transformation parameters which were recently published by the Office of the Surveyor-General of the Federation, OSGOF, various sets of transformation parameters were determined by different multinational oil companies for use in Nigeria. This is because, positions are determined with respect to the local datum/ellipsoid adopted for geodetic computation in each country. The accurate computation of positions of points from DGPS/GNSS observations acquired on the WGS84 ellipsoid in each country requires the application of transformation parameters. ![]() The comparison results show that Columbus and AllTrans software are more suitable for transformation between WGS84 and Minna datums. ![]() The transformed and converted coordinates of the points were compared with the rectangular coordinates of the points obtained with Compass software to determine which of the software is most suitable for application between WGS 84 and Minna datums. The WGS 84 geographic coordinates were transformed and converted to rectangular coordinates on the Minna datum using Columbus, AllTrans and GeoCalc software. The positions of five points obtained from the processing of GNSS observations using Compass post processing software were used. Since positions are computed on the local ellipsoids adopted for geodetic computation in various countries and as some of the geographic positions of the reference/control stations in Nigeria were determined on the WGS 84 ellipsoid, this paper has comparatively analyzed three geodetic datum transformation software with a view to determining which of them is most suitable for transformation between WGS 84 and Minna datums. The procedures and feasibility of obtaining these coordinates in the two systems from the processing of the observations have been demonstrated with Compass post processing software. Consequently, this paper presents detailed procedures and feasibility of obtaining directly NTM or UTM coordinates from post processing of DGPS observations on the Nigeria Minna datum using the appropriate belt or zone parameters and post processing software that accompanied the DGPS/GNSS receivers. But most users of these post processing software process these observations in NTM rectangular coordinates and subsequently convert the NTM grid coordinates to UTM grid positions which are not always correct. 1 Eye4Software Coordinate Calculator v.3.0Ĭonvert coordinates, gps coordinates conversion, coordinates conversion, coordinate system calculator, transverse mercator, stereographic, albers equal area, lambert conformal conic, polar stereographic, krovak, gauss kruger, utm, cassini soldnerĢ Geo Data International (English) v.1.The direct determination of NTM and UTM plane rectangular coordinates from post processing of static DGPS/GNSS observations on the Nigeria Minna datum using post processing software is feasible if the rectangular NTM or UTM coordinates of the control/base station are known, and the belt or zone in which the observations were acquired is accurately identified and the identified belt or zone parameters correctly applied during data processing.
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