I've mentioned this on the mailing lists, but thought I'd bring it up here. I've been thinking more and more about a tool to conflate (match/merge/sync) nodes in OSM data with external data (or even itself), and how useful it would be. For my particular interests it would be useful for merging bus stop and interstate exit data I've recently obtained, as well merging the latest GNIS records. It could even be used to merge address data on nodes with building polygons.

I've sketched out a possible work flow for such a tool, a possible algorithm, and took some notes on a possible JOSM plugin, including a mockup of a configuration dialog. I would appreciate any input or assistance.

http://wiki.openstreetmap.org/wiki/Conflation/Nodes