A methodological framework for assessment of accuracy of a DEM product is described using four case studies (Booschord in the Netherlands, Calabria in Italy, Fishcamp in USA and Zlatibor in Serbia). Focus is put on evaluating the true accuracy of ASTER GDEM using LiDAR data aggregated to 30 m resolution. Three aspects of accuracy have been evaluated: (a) absolute accuracy of elevations (goodness of fit between true and GDEM elevations), (2) accuracy of stream networks (goodness of fit for buffer distance maps for stream networks), and (3) accuracy of surface roughness parameters (goodness of representation of nugget variation and residual errors).
Procedures are explained how to assess:
Accuracy of absolute elevations (absolute error);
Positional and attribute accuracy of hydrological features (streams, watersheds, landforms etc);
Accuracy of surface roughness (i.e. representation fo the short-range variation);
The script is attached to the paper indicated below.
|GDEM_assessment.R||9.48 KB||402||13 hours 46 min ago|