We’ve got a bunch of KML files that we’d like to convert to OSM. We have found a way to do the conversion, but it’s nasty… our map guys says “I do all of my editing in ArcGIS then convert the shp to GPX using DNRgarmin then convert to an osm in gps babel” .
When I bring the resulting sample OSM file into JOSM and vaildate it I get 40 Warnings.
There are plenty of tools for doing direct conversion of ESRI shape files to OSM XML format. These are a bit less of a pain than the technique you’ve used.
Check out the following on the wiki: shp2osm, ogr2osm, Merkaator (can directly read shape files). Its also possible to push SHP files to PostGIS and then use SQL to populate a ‘simple’ pgSQL schema & pull data out with osmosis. All of these processes are non-lossy with respect to data attributes.
A particular problem with standard conversion techniques from shape is the creation of duplicate nodes (nodes in the same position, usually belonging to two shapes in the original file). The validator can be used to fix them (it just merges the nodes). So it may be that your validator problems are pretty trivial.