Digital Geography

GDEM V3 vs SRTM 1: a comparison

Some time has past since I last wrote a DEM comparison, comparing ALOS World with SRTM 1 and GDEM V2 with SRTM 3. But as NASA and METI released the lates version of the ASTER GDEM dataset, I will compare this once again for a certain area in central Mongolia. But this time, the competitor will be SRTM 1.

Short Announcement: SRTM 1 Data Worldwide

The digital elevation dataset resulting from the SRT Mission in the year 2000 is probably the most widely used digital elevation dataset in the world. It was first released with a 90 at ground resolution in a more or less global level (56° S to 60° N). In 2014 the White House announced the release of the 30 m original solution dataset. So they released parts of the dataset one-by-one. Our author Christoph just mentioned an update via Twitter.

DEM comparison: SRTM 3 vs. ASTER GDEM v2

Let’s get ready to rumble! No, just kidding. We are all excited about the recent message from the white house: SRTM “1” (1 equals 1 arcsecond, whereas 3 was indicating the 3 arcsecond a.k.a. 90m DEM) or the official title SRTM-2 will be available for free in the next months (orig. here, dg here). So why is it so important? Most DEM-interested people will answer: “Use the ASTER DEM if you need 30m!”. But let us have a closer look on both systems and how they perform.

Version 2 ASTER Data now available

Since one month, the 2nd version collection data of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) are now available online. This data is now worldwide available for free and is made possible by the NASA and the METI. Even if according to NASA the data is produced with the same gridding as the first version, some large improvements have been made, such as: