20 years of HRSC images
For its usual surface images, the HRSC normally photographs Mars from an altitude of about 300 kilometers, at about the point from which the elliptical orbit of the Mars Express satellite is closest to the planet. The resulting views of the Martian surface have a spatial resolution of up to 12.5 meters per pixel and cover areas about 50 kilometers wide. Thanks to its four colour channels (red, green, blue, infrared) and five panchromatic nadir, stereo, and photometric channels, the stereo camera can visualize Mars not only in three dimensions, but also in color.
For the global data product presented here, however, 90 individual images were used, taken from higher altitudes (roughly between 4000 and 10,000 km) above the Martian surface and thus covering areas around 2500 kilometers wide on average at lower spatial resolution (between 200 and 800 m/px) (image 3). Such large-scale images are typically obtained to observe weather patterns on Mars. If no clouds or other atmospheric phenomena are visible on the images, they are excellent for creating global views of the Martian surface.