Hi wonderful humans - Ben from CalTopo here. Someone sent us this thread in our help forums asking about offline downloads and storage on SD cards, hope you don't mind if I jump in here and share.
CalTopo offline downloads are a feature of a paid account. Utilizing caching to try to download tiles will be at best unreliable and we really do not recommend it if CalTopo is the navigation method you're relying on. Tiles cache at a specific location and zoom level and its hard to ensure you hit every spot to cache them. Caches are intended to speed up app performance primarily.
We did enable storage of map tiles on SD cards, but you cannot save directly from the app due to how Android likes to restrict things. Instead if you download tiles and then move them to your SD card using a 3rd party app or computer it will work. We hope to improve this in the future but at this time that's the reality.
Looks like someone posted the iOS beta link, thats an open beta, feel free to use it! More info is available in the CalTopo blog. You'll see the iOS version in the app store soon, but Apple is slow to approve apps.
If you ever have problems or feature requests please reach out directly to us at
[email protected], we'd love to support you!
Happy trails.