Long description

This figure consists of two parts. The left hand side is a false-coloured topographic map of the martian surface at Nirgal Valles. It is mostly orange coloured, but circular features (imact craters) are green, indicating low elevation. In the centre of the image a long box is overlain, containing a smaller box, highlighting where HRSC observations were made. The right hand side is a repeat of Figure 14 – the greyscale photograph of the martian surface taken from orbit by the spacecraft Mariner 9. This is part of the same area as that shown in the left had photograph of this figure.