Digital Elevation Model Data Sources
Want to elevate your chances of finding a digital elevation model (DEM) data?
Sure you do.
Let’s dive into our list of free global DEM data sources:
1. Space Shuttle Radar Topography Mission (SRTM)
NASA only needed 11 days to capture Shuttle Radar Topography Mission (SRTM) 30-meter digital elevation model. Back in February 2000, the Space Shuttle Endeavour launched with the SRTM payload.
Using two radar antennas and a single pass, it collected sufficient data to generate a digital elevation model using a technique known as interferometric synthetic aperture radar (inSAR). C-Band penetrated canopy cover to the ground better but SRTM still struggled in sloping regions with foreshortening, layover and shadow.
In late 2014, the United States government released the highest resolution SRTM DEM to the public. This 1-arc second global digital elevation model has a spatial resolution of about 30 meters. Also, it covers most of the world with an absolute vertical height accuracy of less than 16m.
Where can you download the SRTM data?
SRTM DEM data is being housed on the USGS Earth Explorer. To download, select your area of interest. Under the data sets tab, select Digital Elevation > SRTM > SRTM 1-ArcSecond Global . But here’s a USGS Earth Explorer download guide to help you get started.
2. ASTER Global Digital Elevation Model
NASA and Japan’s joint operation was the birth of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). As part of this project emerged the ASTER Global Digital Elevation Model (GDEM).
ASTER GDEM boasted a global resolution of 90 meters with a resolution of 30 meters in the United States. Despite its high-resolution and greater coverage (80% of the Earth), dissatisfied users expressed issues with its artifacts often in cloudy areas.
ASTER GDEM used stereoscopic pairs and digital image correlation methods. Based on two images at different angles, it used stereo pairs and photogrammetry to measure elevation. However, the amount of cloud cover affected the accuracy of ASTER which wasn’t the case for SRTM DEM. Because of how passive and active sensors work, this had the most significant effect on quality of DEM.
But over time, ASTER DEM data has improved its products with artifact corrections of their own. In October 2011, ASTER GDEM version 2 was publicly released, which was a considerable improvement.
Despite its experimental grade, ASTER GDEM-2 is considered a more accurate representation than the SRTM elevation model in rugged mountainous terrain. But you should really take a look for yourself.
Where can you download the ASTER GDEM?
You can download the ASTER DEM data for free from the USGS Earth Explorer. Under the data sets tab, select Digital Elevation > ASTER .
3. JAXA’s Global ALOS 3D World
ALOS World 3D is a 30-meter resolution digital surface model (DSM) captured by the Japan Aerospace Exploration Agency’s (JAXA). Recently, this DSM has been made available to the public.
The neat thing about is that it is the most precise global-scale elevation data now. It uses the Advanced Land Observing Satellite “DAICHI” (ALOS) based on stereo mapping from PRISM.
Where can you download the JAXA’s Global ALOS 3D World?
If you want this accurate DSM, you’ll have to register online through the JAXA Global ALOS portal to download it.
4. Light Detection and Ranging (LiDAR)
You might think that finding LiDAR is a shot in the dark.
But it’s not anymore.
Slowly and steadily, we are moving towards a global LiDAR map.
With Open Topography topping the list at #1, we’ve put together a list of some of the 6 best LiDAR data sources available online for free.
Because nothing beats LiDAR for spatial accuracy. After you filter ground returns, you can build an impressive DEM from LiDAR.
And if you still can’t find anything in the link above, try your local or regional government. If you tell them what you are using it for, they sometimes hand out LiDAR for free.
5. Mars Orbiter Laser Altimeter (MOLA)
Just throwing this out here to pique your interest.
We aren’t only mapping out Earth’s elevation.
Based on the Mars Orbiter Laser Altimeter (MOLA) instrument, you can view the rugged terrain of Mars. For example, this Mars Terrain map uses data from MOLA.
In fact, scientists used MOLA to map out ancient streams on Mars. If this doesn’t excite you, I don’t know what would.
Where can you download the MOLA DEM of Mars?
The USGS Astrogeology Science Center is the DEM data hub for Mars. USGS found elevations above the areoid from a Martian gravity field solution GMM-2B with a total elevation uncertainty of at least ±3m.
Who said GIS wasn’t fun?
How to Download DEM Data
Elevation data is abundant.
It’s just a matter of finding the right one to suit your needs.
From spaceborne to airborne, from Earth to Mars – you now have the right tools to position yourself vertically on any location of the planets.
Got anything else? Let me know with a comment below.