WW2D is cross-platform, free and open-source version of NASA World Wind software, see http://worldwind.arc.nasa.gov for details. WW2Dallows you to explore Earth using satellite imagery, topographic maps and image from other data sources also providing large placenames and boundaries database and allowing you to install community-made add-ons for even more information about our planet.
</p><p align="justify">In basic configuration WW2D uses images from Blue Marble (1 km/pixel), LandSat7 (15 m/pixel), USGS Topo Maps, USGS Digital Ortho imagery, USGS Urban Area imagery.
</p>WW2D is designed to dynamically download needed data from internet, however you can download data you want for faster access and offline usage.