Credit: NASA

Humans have strived for a cartographic representation of their world for thousands of years. Mapping the Earth was one of the motivations of the early explorers, and armies of surveyors have worked towards an accurate description of the topography of the globe. With satellite data giving us an unprecedented overview of our planet, cartography has reached new heights. Now an accurate map of (almost) the whole Earth has become available.

Thanks to the efforts of the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and NASA's satellite Terra, 99% of the Earth's surface topography has been measured at a resolution of about 30 m. A digital elevation map covering the planet from Peary Land at the northernmost edge of Greenland right into the centre of Antarctica's Ross Ice Shelf — or from 83° N to 83° S — was released at the end of June.

The map is based on almost 1.3 million individual photographs taken in stereo pairs by the ASTER instrument — such as the one from the Bhutan Himalayas shown here with an image in natural colour obtained with the same instrument draped over it. The digital elevation model is freely available online (http://www.gdem.aster.ersdac.or.jp) — or will be, once the servers have caught up with the high demand. At the point of writing, potential users are warned that sessions may be disconnected before the download has started, because of excess traffic to the site.

ASTER's topographic data set substantially expands the coverage of the preceding data set, which included 80% of the Earth's surface, between the latitudes 60° N and 57° S. Now only the poles and their immediate surroundings remain to be charted.