THREE YEARS OF MARS CARTOGRAPHY USING HRSC DATA
J. Albertz1, S. Gehrke1, H. Lehmann1, M. Waehlisch2, G. Neukum3
1 - Technische Universitaet Berlin, Geodesy and
Geoinformation Science
2 - German Aerospace Center (DLR), Institute for Planetary
Exploration
3 - Freie Universitaet Berlin, Institute of Geosciences
albertz@igg.tu-berlin.de
Since
January 2004, the High Resolution Stereo
Camera (HSRC) on board of Mars
Express is imaging the Martian surface. The data acquired provide both full
color and systematic stereo; it is well suited to derive color orthoimages,
Digital Terrain Models, and, based on that, topographic and thematic maps. The
standard map series of the Mars Express
mission is the Topographic Image Map
Mars 1:200,000. The planet Mars is covered by altogether 10.372 sheets in
equal-area map projections, 10,324 of them in Sinusoidal Projection, supplemented by 48 polar sheets in Lambert Azimuthal Projection. The
series’ layout scheme is flexible to the generation of special target maps,
thematic maps, and related products.
In order to
automate the generation of such maps, the cartographic
software package Planetary Image Mapper
(PIMap) has been developed at Technische
Universität Berlin. The map production is predominantly carried out at the university in
collaboration with the German Aerospace
Center (DLR), which is responsible for photogrammetric processing of HRSC
data. Other HRSC Team members are involved, especially with regard to thematic
mapping.
An average
sheet of the Topographic Image Map Mars
1:200,000 displays approximately 120x120 km; considering an HRSC image
width of 60 km in highest resolution of 12 m/pixel, it is evident that mosaics
of adjacent orbits are necessary to cover the mapped area. Therefore,
especially in the early stage, map sheets needed to be adapted to individual
orbits by location and/or scale. The first maps within the regular sheet lines
could be generated in summer 2004. Until the present day, a variety of
topographic and also thematic maps of different Martian regions has been
produced – including, e.g., the first large-scale maps of the north-polar
region, which combine HRSC imagery and Mars
Orbiter Laser Altimeter (MOLA) contours.
Furthermore, it has been shown that HRSC data of highest resolution are
suitable for mapping in scales up to 1:100 000 and even 1:50 000, which can be
systematically achieved by dividing standard sheets into quarters and
sixteenth, respectively. A benefit of future map sheets will be the inclusion
of the Catalog of Large Martian Impact
Craters (companion abstract by Gehrke
et al.).
In
conclusion, the Topographic Image Map
Mars 1:200,000 series has proven to be a useful and guide-lining standard.
From the experience gained during three years of HRSC cartography and
operational application of the software PIMap it is clear that we are well
prepared for systematic map generation from HRSC data.