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In 1999, the US and Japan jointly launched the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) into orbit. One of the goals of the ASTER instrument mission was to conduct detailed terrain mapping of the surface of the earth.

Colorized ASTER GDEM Map of Africa

The ASTER global digital elevation model (GDEM) covers the planet from 83 degrees north to 83 degrees south at 1 arcsecond resolution and is the "most detailed 3d map of the Earth ever made."

In June of 2009, the ASTER GDEM was released to the public.

For us as builders of long distance wireless networks, this is mostly of interest because it allows us to do more accurate computer modeling of radio lines of sight to answer the basic question "If I build antennas at point A and point B...can they talk to each other?"

If you want to try it out for youself, see our detailed technical guide on how to download and convert this data to a format compatible with RadioMobile, the widely used free software for modeling radio propagation.

• Obtaining ASTER GDEM Data and Converting to SRTM1 for Use With RadioMobile

We recommend ASTER GDEM in addition to SRTM3 (previously the highest global terrain model available) as some of our partners in Nepal have had significant difficulties with "voids" or blank spots in the SRTM3 data right in the middle of their project sites.

Using SRTM3, RadioMobile will tell you a line of sight through a void will work, when in the real world it might not. We have seen significantly fewer voids in the ASTER GDEM data. If SRTM3 has voids where you need to plan a link, try the ASTER data.