Proposal of the Processing Parameters for the Conversion of Rectangular Coordinates of the Luanda Province from Ellipsoid Clark 1880 to WGS 84

Abstract

The geodetic activity in Angola has seen a tremendous advancement with the advent of global positioning systems via Artificial Earth Satellites (AES). The capacity of such systems permits users to locate with high degree of accuracy any object on the surface of the ground. Such ability coupled with its speed of execution and availability makes AES a far superior methods of observation than its predecessors. However, the adoption of the World Geodetic System (WGS 84) creates a need to update the cartographic literature currently in use, from the Ellipsoid Clark 1880 system, a topocentric system, to the WGS 84 System, a geocentric system. The present article intends to use the transformation conforme to the determination of the transformation parameters in the Province of Luanda. The methodology used for this project is fundamentally based on, as far as its procedures, a descriptive research where the deductive scientific method used is based on the results obtained from the data gathered. The results are thereafter presented in statistical form. This study utilizes 8 points from the Geodetic Network of Angola (GNA) and rectangular coordinates referenced from Ellipsoid Clark 1880 and WGS 84. Solved the system of normal equations, were estimated four parameters of conversion of Luanda (ΔX= -195.9722 metros; ΔY= + 53.8010 metros; γ = 1.5708 arcseg; m = 0.9999), based on the method of minimum squares. To evaluate the results, a comparison was made between the differences in coordinates estimated by the adjustment and any known reference values. The results demonstrate that the model is appropriate for the conversion of cartographic bases with a scale equal or smaller than 1:5000.