Modern Development for the Improvement of Accuracy of Nigerian Coordinate Transformation Process Using the Adapted NTv2 Model: The Critical Issues of the Mathematical Algorithm

Changing coordinates using appropriate mathematical models from one reference system to another may be influenced if the operation requires the change of datum. A set of transformation parameters has been adopted for Nigeria. However, the critical concern usually associated with the problem of transformation of coordinates is the issue of recoverability of the original values of transformed coordinates. The recursive effect of variables associated with spatial problems can be aptly modelled with an appropriate algorithm that set out a process to achieve a definite output. Consequently, the main thrust of this paper is to highlight the critical elements of the mathematical algorithm associated with the National Transformation Version 2 (NTv2) model adapted for the Nigerian Datum Transformation process. The adapted NTv2 model adopts the bi-linear interpolation approach and the covariance function obtained were used to generate transformation elements in latitude (Δφp) and longitude (Δλp) and corresponding accuracies at the lattice nodes. The mathematical algorithm of this adapted NTv2 model underscores the likely attainment of better and significant values and statistical indicator of the improved accuracy as the average shift values for latitude and longitude for any transformed points in Nigeria. This capability makes the mathematical algorithm to be adaptable and fit for the purpose of the transformation process. The improvement in the positional accuracy is directly attributable to the application of the NTv2 model which provides a flexible and robust system of modelling any inherent systematic error in the national network.

A high-level architecture for a Geomatics Informatization Technology System: the Chinese case

China will,as a component of‘Digital Earth,’establish a Geomatics Informatization Technology System(GITS)which is characterized by real-time acquisition,automatic processing,networking service,and socialized application with fundamental geographical information.The basic composition of GITS is proposed.GITS covers four layers and six platforms.The four layers are data acquisition,processing,management,and application and services.The six platforms are informatic geodetic datum,high-precision geo-spatial data acquisition,automatic geo-spatial data processing,grid-based geo-spatial information management,comprehensive geo-spatial information sharing and service,and geo-spatial information integration and application.The informatic geodetic datum platform provides a carrier for all the four layers and a base for the other five platforms.The high-precision geo-spatial data acquisition platform belongs to the acquisition layer.The automatic geo-spatial data processing platform belongs to the processing layer.The grid-based geo-spatial information management platform belongs to the management layer and is a bridge connecting geospatial data acquisition and spatial information sharing service and integrated applications.The comprehensive geo-spatial information sharing and service platform belongs to the application and service layer.Finally,this paper presents thoughts for constructing GITS.