Portable OpenStreetMap

Portable OpenStreetMap or "POSM" is project to bring together assorted OpenStreetMap tools onto a portable device which works without an internet connection. POSM is being developed by the American Red Cross with humanitarian field mapping in mind.

Portable OpenStreetMap on github has more description plus code and issue tracking.

As well as special integration approaches for working offline, one key development is the POSM Replay Tool, which allows a parallel OpenStreetMap database and editing API to re-sync changes with the main OpenStreetMap database Blog: Merging Offline Edits with the POSM Replay Tool gives details. It's an implementation of the Satellite API Instances idea.