An animated comparisons of hill shades derived from free 90-m SRTM, free 30-m ASTER GDEM and reasonably priced 8-meter DigitalGlobe Mapping DSM elevation data. (Data Sources: CIGAR, ERSDAC and DigitalGlobe)
Utilizing their constellation of two 50-centimeter WorldView satellites, DigitalGlobe is able to offer a global solution to a historic challenge in the geospatial world – i.e. access to high-quality, recent and reasonably priced elevation data for nearly any location on the planet. There are three product levels offered in the AES, each with differing resolutions, accuracies and price points to meet the specific needs of your project. Further, DigitalGlobe offers both a digital surface model (DSM) where human-made and natural features such as buildings, cars, trees, etc. are present in the elevation data; and a digital terrain model (DTM) where these obstructing features are removed.
In this short piece, we would like to give our readers a sense of the entry level AES product – i.e. the 8-meter Mapping elevation model – and how it compares to the various sources of free data that can be found online. In the first animation below, we have prepared a stack of elevation data from southern Germany that has been displayed using the same color ramp. In this color ramp, the lowest areas are in red and the highest are in green. The first image is free 90-meter (m) SRTM data which can be downloaded from a variety of US and international government website (for instance here). The second image is also free data but this time 30-meter ASTER GDEM data which can be downloaded here once you register. The final image is a sample of the entry level Mapping DSM from DigitalGlobe with 8-meter resolution.
In the second animation, we used the same datasets but this time displayed each as a ‘hill shade’ so that elevations are more visually apparent. In both of these animations, you can see the level of detail in the Mapping DSM which you simply cannot get in the free sources we all know and use online.
Priced below many other choices with global coverage, DigitalGlobe’s AES elevation suite is the ideal solution for:
- Regional studies which require an analysis of elevation.
- Academics in need of a reasonably-priced solution to replace dated and low resolution public sources.
- Engineers looking to replace costly field labor in distant lands.
- More accurate orthorectification, particularly in areas of high topographic change.