Error analysis between inverse distance weighting and polynomial methods of local orthometic height determination

Error in orthometric height determination is crucial for geodetic application in solving problems of surface topographic problem. Results obtained through various methods and procedures gives varied results. The accuracy in locally derived orthometric height depends on the method, technique and modelling system of its derivation. The study provides analysis on the relative accuracies between local orthometric heights derived using polynomial and inverse distance weighting (IDW) surface model. Orthometric heights from Nigerian triangulation network and GPS ellipsoidal height were used. Results from both the techniques were analysed using statistical variables for internal consistency and field validation. Polynomial happens to provide higher error in internal consistency but more precise result on field application while IDW showing the reverse case. Having yielded better results, polynomial model is recommended for local orthometric height determination.