8 * 9 km
used software: Quantum GIS, GIMP, Blender 2.6.1.
Steps:
-scan an old map (doesn't matter how badly)
QGIS
-use the georefence tool in QGIS to callibrate the scan
-add a polyline vector layer and vectorize the contours
-using the interpolation plugin, make the grayscale raster as a basis for textures
-make the diffuse map in QGIS and save it in the same size as grayscale
In GIMP
-add transparency to the scan using layer mask
In blender.
-set a grid the same size as desired DTM
-subdivide it as much as you can (simple subsurf)
- use displace modifier on your grid (be careful to preserve your height scale (eg *2)
- bake normal maps on a low poly version that also has a displace modifier
- add diffuse and transparent black layer
That's it. It is possible for free.
