JOSM is an editor for OpenStreetMap (OSM) written in Java
Currently it supports loading stand alone GPX track data from the OSM database,
loading and editing existing nodes, ways, metadata tags and relations.

OpenStreetMap is a project aimed squarely at creating and providing
free geographic data such as street maps to anyone who wants them.
The project was started because most maps you think of as free actually
have legal or technical restrictions on their use, holding back people
from using them in creative, productive or unexpected ways.