Roessner, Sigrid
the Maili-Suu river basin (Fig. 1). Like the whole region, this test area is part of the active tectonic collision zone
between the Eurasian and the Indian Plates. Ongoing tectonic activity results in an active development of the Pamir-
Tien Shan orogen causing earthquakes and mass movements (landslides, rock falls). Landslides mainly occur at
elevations between 700 and 2000m in weakly consolidated sediments of the topographically rising rim of the Fergana
Basin below its transition into the high mountainous terrain.
72*30'E 73*00' E 73?30' E
Position of GPS points
X Plain
+ Valley
Oo Hill slope
Test area X — Hill top
Maili-Suu
aZ Reference lar oo
m stations N
MOMS-2P
DEM
Kilometers
ay 30°
20 0
Fig. 1 DEM (50m raster size) derived from stereoscopic MOMS-2P data overlaid by GPS check points
2 INPUT DATA FOR DEM GENERATION
Remote sensing based DEM generation requires stereo image data, precise 3-D coordinate information of ground
control points (GCP) and independent check points (CP). MOMS-2P data were acquired in stereo mode D on the 29^ of
June 1998. Topographic ground control information were obtained by geodetic GPS observations in July 1999. In the
following two sections both input data sources are described in more detail.
21 MOMS-2P data
MOMS (Modular Optoelectronic Multispectral Scanner) is a German spaceborne pushbroom scanner for high
resolution (HR), multispectral (MS) and threefold along-track stereoscopic imaging (Kaufmann et al., 1989; Seige et al,
1999), The stereo-module consists of a HR nadir looking lens with a focal length of 660mm and two inclined lenses
with 237mm focal length. Thus, the Earth’s surface is imaged three times from three different directions within
approximately 40 seconds only, corresponding to an orbital distance of approximately 300km. This along-track stereo
principle is highly advantageous for image correlation in the data evaluation process, since all three image strips are
recorded under more or less the same imaging conditions. The stereo angle of 21.4° results in a base/height ratio of
approximately 0.8. The multispectral-module consists of two additional lenses with 220mm focal length comprising 2
CCD arrays for narrow-band image acquisition in the blue, green, read and near infrared wavelength ranges.
1260 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.