This service was created by Jochen Topf and Christoph Hormann for the OpenStreetMap community and the general public. Jochen has been an active member of the OSM community since 2006. He works as a freelance consultant and software developer specializing in geodata and OpenStreetMap. More information about Jochen can be found on jochentopf.com Christoph is working as a freelance geovisualization designer with focus on large area maps and 3d visualizations. You can find out more about Christoph on imagico.de. Writing the Open Source software behind this site and maintaining and improving this service takes a lot of time. Please consider supporting this effort. OpenStreetMap uses the WGS84 spatial reference system used by the Global Positioning System (GPS). It uses geographic coordinates between -180° and 180° longitude and -90° and 90° latitude. So this is the ‘native’ OSM format. The map area of such maps is a square with x and y coordiates both between -20,037,508.34 and 20,037,508.34 meters. As a result data north of about 85.1° and south of about -85.1° latitude can not be shown and has been cut off. The correct EPSG code for this data is 3857 and this is what the data files show. Before this code was allocated other codes such as 900913 were used. If your software does not understand the 3857 code you might need to upgrade. See this page for all the details. Source.