I have shapefile with roads. I want to digitize some of the objects in shapefile to OSM, because I allways use OSM shapefiles and I have something to give to. What software should I use? I have JOSM installed. Is it enough?
JOSM can not read shapefiles directly.
For that reason I have QGIS installed, where I can view my shapefiles on OSM background via Openlayers plugin.
QGIS is able to export shapefiles of type
line to gpx format (which can be loaded into JOSM) as a separate layer with
Save As .... The coordinate reference system must be reprojected to WGS84 if necessary. In the options,
FORCE_GPX_TRACK must be set to
Skip attribute creation must be checked.
In JOSM, you can download OSM raw data along the gps path, and then start to create new ways and points, or move or extent existing elements. Simply uploading new features is not encouraged, because they must fit existing to elements, or been connected to them.
If you have polygon shapefiles, you have to transform them in QGIS to closed lines with
Vector -> Geometry Tools -> Polygons to lines , because gpx format does not know polygons.
Shapefiles can be directly loaded in JOSM, after you install opendata plugin. Beware that importing data from shapefile is not considered good as it has to mix the more complex osm data structure. Also you have to consider the source and license of the shapefile. You can only contribute data which is compatible with osm's ODBL license.