JOSM, which stands for Java OpenStreetMap editor, is a desktop program developed originally by Immanuel Scholz. It is the primary offline editing program for OpenStreetMap (OSM). OSM is a project designed to create a free editable map of the globe. As a free-source data repository of all roads in the world, it is a product of crowdsourcing and the editing efforts of different conributors. Usage of its data is found in online mapping services such as those of MapQuest, Geocaching.com, Foursquare, and Craigslist. It is also employed for other purposes, like replacing data normally included in GPS receivers.
Written in Java 1.6 or higher, JOSM lets users can add streets and other data to OSM from loaded GPS (Global Positioning System) tracklogs. The application is a feature-rich editor meant for OSM mappers. The reason for this is that some installation and configuration settings require computer expertise. It is advisable to use this offline editor if any of the following applies:
• The mapper wants to modify large quantities of data.
• The mapper intends to test-run a task or action by modifying data without causing any immediate and permanent effects.
• The mapper wishes to display photos taken of given track
• The area targeted for editing is currently being changed by others, wherein JOSM handles changes and conflict that may stem from modified areas