Abstrakt: | Digital elevation models (DEMs) play a significant
role in geomorphological research. For geomorphologists
reconstructing landform and drainage structure
is frequently as important as elevation accuracy. Consequently,
large-scale topographic maps (with contours,
height points and watercourses) constitute excellent material
for creating models (here called Topo-DEM) in fine
resolution. The purpose of the conducted analyses was
to assess the quality of Topo-DEM against freely-available
globalDEMs and then to compare it with a reference model
derived from laser scanning (LiDAR-DEM). The analysis
also involved derivative maps of geomorphometric parameters
(local relief, slope, curvature, aspect) generated on
the basis of Topo-DEM and LiDAR-DEM. Moreover, comparative
classification of landforms was carried out. It was
indicated that Topo-DEM is characterised by good elevation
accuracy (RMSE <2 m) and reflects the topography of
the analyzed area surprisingly well. Additionally, statistical
and percentage metrics confirm that it is possible to
generate a DEM with very good quality parameters on the
basis of a large-scale topographic map (1:10,000): elevation
differences between Topo-DEM and: 1) topographic
map amounted from−1.68 to +2.06 m,MAEis 0.10 m, RMSE
0.16 m; 2) LiDAR-DEM (MAE 1.13 m, RMSE 1.69 m, SD 1.83
m); 3) GPS RTK measurements amounted from−3.6 to +3.01
m, MAE is 0.72 m, RMSE 0.97 m, SD 0.97 m. For an area
of several dozen km2 Topo-DEM with 10×10 m resolution
proved more efficient than detailed (1×1 m) LiDAR-DEM. |