Abstract
The standard spheroidal reference surface also referred as the reference ellipsoid is a part of mapping basic infrastructures of a country. In Cameroon, the ellipsoid Clarke 1880 with unknown parameters used for a long time as reference system in basic mapping, has lead to the use of World Geodetic System 1984 (WGS 84) whose parameters are well known. Meanwhile, the latter is not accurate locally due to the fact that the best ellipsoid is the one that fits very well with the local geoid. In order to look for the parameters of the local ellipsoid that fits best to the local geoid (Cameroon Geoid Model 2011 (CGM11)), the Global Positionning System (GPS) data made of 525 geodetic ground control points of the new geodetic network of Cameroon set up in 2011 were used. These GPS measures provide for each point the values of the ellipsoid height and the elevation which are used to determine the parameters of the local ellipsoid model for Cameroon through the least square form of the Molodensky analytical method. The results are given as the difference in ellipsoidal height relative to the parameters of the WGS84 ellipsoid assuming the two ellipsoids in their parallel. These results show that the obtained ellipsoid fits better to the local geoid with 1.072 m as the standard deviation value, is improved considerably in comparison to the previous studies conducted in Cameroon whose standard deviation was fairly equal to 1.679 m.
Highlights
The basis cartographic infrastructure is characterized by a mapping reference system made of the ellipsoid, representing the mathematical model of the earth surface
In this case we are looking for a local ellipsoid parameters in Cameroon knowing the parameters of a global WGS84 ellipsoid and with the Global Positionning System (GPS) data made of 525 points of the geodetic network of Cameroon
We assume that the parameters of the first ellipsoid are well known and we look for the parameters of the second ellipsoid that fits best to the local geoid
Summary
The basis cartographic infrastructure is characterized by a mapping reference system made of the ellipsoid, representing the mathematical model of the earth surface. The Molodensky simplified formula enables the transformation of the coordinates of a point between two different ellipsoid parameters when processing parameters are known [4]-[6] In this case we are looking for a local ellipsoid parameters in Cameroon knowing the parameters of a global WGS84 ellipsoid and with the GPS data made of 525 points of the geodetic network of Cameroon. This problem is solved by applying the least squares method to the simplified formula Molodensky [7]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.