I am using QGIS to calculate the terrain slope, starting from vector contour line data. Using linear interpolation like
r.surf.contour gives me a reasonable looking DEM, but is not really useful if I need realistic slope data. I have seen a lot about Kriging point data, but it is not something I have tried before and also I have a large number of points – more than you would normally use for Kriging. Should I Krige the point data or is there a simpler way of getting a smooth slope?
1. The DEM linearly interpolated from contour data
2. Slope of the DEM — the linear interpolation is clearly visible
3. Nodes from contour vectors — too many for Kriging?