elevation source: local DTM

[JeromeSchmied]

Hi, I haven't tried this program yet, but looks promising!

But there's one drawback I've spotted in the README: elevation data comes from the internet, which I guess is quite slow and limited. I've been working on fit2gpx-rs lately and wanted to add elevation data for many-many waypoints at once. At first I tried some open APIs (although not the same ones as You do), but found out it's not good enough, so I've started using DTM(Digital Terrain Model)s, more exactly HGT files, such as the ones found here: Sonny's collection (this is only for europe, but there are several great sources).

IMO local DTMs are lot better for this use case. Actually, (a little self-promotion never hurt anyone:) I'm developing a neat library for parsing HGT files (one could use .tiff ones as well, I didn't like them somehow), You may consider utilizing for this project, I'd be more than happy to help.

Tell me what You think!

Best wishes,
Jerome

[JeromeSchmied]

https://viewfinderpanoramas.org/Coverage%20map%20viewfinderpanoramas_org3.htm

seems like a great source for the us, although it's resolution isn't very high

[JeromeSchmied]

https://apps.nationalmap.gov/downloader
looks promising, I'd consider using it