Accuracy assessment and conflation of DEMs over Kaduna State, Nigeria

Abstract

Digital Elevation Models (DEMs) are a type of raster data layer in which each cell has a value corresponding to its elevation (z-values at regularly spaced intervals). This study assess the vertical accuracy of four freely available DEMs (AW3D, ASTER SRTM and ALOS-PALSAR) over two test sites (hilly and plain) with reference to ground controls available on the test sites. However, to obtain a much higher resolution DEMs, these DEMs were fussed using Multiple Linear Regression Model and the performance of the fused DEM was tested over the hilly and plain terrain. At the plain terrain, ASTER DEM is closer to those of the GCPs (ground survey) than those of the ALOS PALSAR, AW3D and SRTM. At the hilly terrain, AW3D is closer to those of the GCPs (ground survey) than those of the ALOS PALSAR, ASTER and SRTM. After conflation, the conflated DEM performed better than the whole DEMs put together in the hilly and plain terrain.