Countour Lines at 100m Intervals. Interpolated (using a kriging interpolator) from a 30 second grid DTM. Grid cell size was set to 500m. The shapefile was produced directly from the grid using elevation intervals of 100m. Positional Accuracy: Interpolated from 1km grid. DTM originally obtained from Geo Business Solutions. Zip file includes elevation and relief, Namibia borders and settlements shapefiles, and detail metadata.