For the past couple of weeks I’ve been busy on extending my digital elevation model (DEM) library with some new features, including the ability to use DEM sources other than the “standard” SRTM3. I’ve managed to produce a working version of the code which supports Viewfinder’s DEM1 data for Alps and I was dying to test it on Julian Alps, especially the area around Triglav, the highest mountain in Slovenia. The SRTM3 data for Julian Alps is very poor, with large chunks of height data missing. Here’s a sample contours map generated in Kosmos using that low-quality SRTM data:

Triglav SRTM

As you can see above, the actual Triglav mountain does not have any contours. Compare that with the contours generated with Viewfinder’s data:

Triglav Viewfinder DEM1

Not only all the contours are there (and seem to correspond with reality), but also the resolution is three times better than that of SRTM3. I’m pretty impressed with Viewfinder’s data, I have to admit.

This is only an intermediate experiment, I have to do some more work on the library before I integrate it into GroundTruth and Kosmos. But the results so far are very promising.

BTW: I contacted Jonathan de Ferranti, the author of Viewfinder’s site, and asked him about terms of use of these DEM tiles. Basically he gave a wholehearted approval of using it for open-source projects as long as the original authorship is respected. He does not claim copyright on these tiles since they originated from various sources, be he still likes to be informed about any large-scale use of them.