Using iMars: Viewing Mars Express data of Valles Marineris
The iMars web-based geographic information system, or iMars webGIS, is an online tool for exploring the wealth of data about Mars collected in past decades.
The iMars webGIS brings together space-based imaging and high-precision 3D data of Mars from Mars Express' High Resolution Stereo Camera (HRSC), which can be displayed alongside a vast quantity of additional datasets and images from other Mars missions. These processed datasets can be used to view the Martian surface across different orbits, missions, and time periods, allowing users to hunt for signs of surface changes, such as landslides, new impact craters, the evolution of the polar caps and frosts, and so on.
This image shows a patch of Mars' surface featuring a vast canyon system named Valles Marineris, which can be seen cutting across the centre of the frame.
The grayscale layer comprises data from the Mars Orbiter Laser Altimeter (MOLA) on NASA's Mars Global Surveyor, on top of which sits a colourful layer comprising single-strip digital terrain model data from Mars Express' High Resolution Stereo Camera (HRSC), colour-coded by topography (blue-greens being depressions, yellows being mid-level, and orange-reds being areas of higher elevation, as indicated by the key in the bottom left). The many black boxes peppering the frame are image footprints from Mars Express' HRSC Nadir (downwards-pointing) channel; the content of three of these (at the centre of the frame) is shown.
The webGIS contains multiple controls and dialogue boxes for navigation, allowing users to select image footprints from different instruments, to display or hide features such as quadrant markers, nomenclature labels, and landing sites, to select footprints and fill with desired data, and to filter data by time period.
Further details about iMars webGIS, and about PSUP–another tool to explore changes on the surface of Mars–can be found here.