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Ensimmäiset Marsin suunnistuskartat   A topographic map sheet of a part of the Iani Chaos region on Mars, based on image data obtained with the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express. Such 'Topographic Image Map Mars 1:200 000' has been designed as an example of a possible standard map series for the HRSC experiment. So far all map sheets are based on HRSC orthoimage mosaics and show contour lines derived from HRSC Digital Terrain Models (DTMs). Furthermore, they feature Martian topographic names (craters, mountains, valleys, etc.), cartographic grids, sheet names, individual designations, and all respective legend entries. Should the outlined map series be realized, the planet Mars would be covered by 10 372 particular map sheets in equal-area map projections – 10 324 of them within the ±85° latitude zone in Sinusoidal Projection, supplemented by 48 polar sheets in Lambert Azimuthal Equal-area Projection. While each of the quadrangles spans 2° in latitude, longitudinal extents increase from 2° near the equator up to 360° toward the poles in order to keep the mapped area approximately constant. Therefore, the general layout of all maps appears very similar; each sheet features an overall width of 830 millimetres and a height of 700 millimetres. The sheets of such a 'Topographic Image Map Mars 1:200 000' standard series as outlined here can be subdivided into sheets of quarters and sixteenths for systematic cartography in larger scale, 1:100 000 and 1:50 000 respectively. Within their mapped surfaces, the sheets differ in image resolution due to their different scales. Although few effects of image compression are recognizable in the largest scale (such as the 1:50 000 map at, for instance, shadowed slopes), in general more texture details of the Martian surface become visible. A contour line equidistance of 250 metres is common for most of the sheets of the 1:200 000 topographic maps. In larger scales, a more subtle representation of the terrain topography is achieved by denser contour lines. All map sheets have been generated using the cartographic software system 'Planetary Image Mapper' (PIMap), which has been developed at Technische Universität Berlin for cartographic presentation of HRSC data. Topographic map contents, graticules, frame lines, map titles as well as typical marginal elements can be generated and/or combined to the digital map sheet with PIMap.
The data were obtained on 5, 8 and 11 October 2004 (during orbits 0912, 0923 and 0934 of Mars Express) with best possible ground resolutions.  Iani Chaos is a large depression with dimensions of 330 kilometres in length and 430 kilometres in width, located at 2.8° south and 342.5° east. Individual blocks of rock and hills form a disrupted, knobby pattern in an apparently 'chaotic' distribution. Terraces and 'islands' are likely remnants of the pre-existing surface, which collapsed after cavities had formed beneath it - ice in these cavities might have been melted by volcanic heat and flowed into Ares Vallis towards the northern lowlands. Due to the hints of water having formed it, such a landscape is of special geological interest but it is also well suited to present the design and the potential of the topographic map series.  This image of Mars taken by the High Resolution Stereo Camera on board ESA's Mars Express outlines the scales (1:200 000, 1:100 000 and 1:50 000) of the series of topographic maps of the planet's surface that can be realized thanks to HRSC data.  A topographic map of an adjacent area of the Iani Chaos region on Mars. The scale is 1:200 000 and the height difference between the contour lines is 250 metres. The data were obtained by the High Resolution Stereo camera on board ESA's Mars Express on 5, 8 and 11 October 2004 (during orbits 0912, 0923 and 0934 of Mars Express).  A smaller scale topographic map of the Iani Chaos region on Mars. The scale is just 1:100 000 and the contour lines are finer, just 100 metres difference, to help bring out more subtle gradations in the height of Martian surface features. The data were obtained by the High Resolution Stereo camera on board ESA’s Mars Express on 5, 8 and 11 October 2004 (during orbits 0912, 0923 and 0934 of Mars Express). Lisätietoa  The smallest scale topographic map of the Iani Chaos region on Mars. The scale is just 1:50 000. The contour lines are now only 50 meters apart. At these smaller scales, more textural details of the surface can be recognised. The data were obtained by the High Resolution Stereo camera on board ESA's Mars Express on 5, 8 and 11 October 2004 (during orbits 0912, 0923 and 0934 of Mars Express). Release date: 12 helmikuuta 2007 |