Exploitation of TerraSAR-X Data for Land use/Land Cover Analysis Using Object-Oriented Classification Approach in the African Sahel Area, Sudan.

Recently, object-oriented classification techniques based on image segmentation approaches are being studied using high-resolution satellite images to extract various thematic information. In this study different types of land use/land cover (LULC) types were analysed by employing object-oriented classification approach to dual TerraSAR-X images (HH and HV polarisation) at African Sahel. For that purpose, multi-resolution segmentation (MRS) of the Definiens software was used for creating the image objects. Using the feature space optimisation (FSO) tool the attributes of the TerraSAR-X image were optimised in order to obtain the best separability among classes for the LULC mapping. The backscattering coefficients (BSC) for some classes were observed to be different for HH and HV polarisations. The best separation distance of the tested spectral, shape and textural features showed different variations among the discriminated LULC classes. An overall accuracy of 84 % with a kappa value 0.82 was resulted from the classification scheme, while accuracy differences among the classes were kept minimal. Finally, the results highlighted the importance of a combine use of TerraSAR-X data and object-oriented classification approaches as a useful source of information and technique for LULC analysis in the African Sahel drylands

Team b

Following the conceptual idea "from 3D camera to 3D view", the production of true-3D image maps for the glasses-free stereoviewing of parts of the Martian surface, is described. The image data have been acquired by the DLR High Resolution Stereo Camera (HRSC) as a part of the Mars Express Mission of ESA. This multi-line scanner delivers digital multispectral scanner data of highest quality in a fore, aft and nadir mode, thus offering a perfect data set for true-3D visualization. A true-colour image-line map in true-3D appears to cover both the requirements of the Mars research community and of the public best. In order to be able to view the map without viewing aids such as polarisation glasses the decision was made to generate it on the basis of lenticular lenses. The present paper demonstrates the workflow from the georeferenced image data set and the DTM to a true-3D visualization. The technology used is based on the principle of lenticular foils. Micro-lenses on a transparent plastic foil allow the map user to view the integral of two or more interlaced strips of stereo-mates through this foil with the left and right eye respectively. The calculation of both the strip width and the interlacing is done by means of commercially available software. Due to the interlacing of the sub-millimeter strips of the stereo-mates below each lenticular lens and the resulting decomposition in x-direction the integration of well-designed and easily legible signatures and letterings represent a challenge, both in terms of threedimensional modelling and cartographic elaboration. Tests and approaches to overcome various constraints in order to generat

Identification of potentially dangerous glacial lakes in the northern Tien Shan

Like in many other parts of the world, the glaciers in northern Tien Shan are receding, and the permafrost is thawing. Concomitantly, glacial lakes are developing. Historically, outbursts of these glacial lakes have resulted in severe hazards for infrastructures and livelihood. Multi-temporal space imageries are an ideal means to study and monitor glaciers and glacial lakes over large areas. Geomorphometric analysis and modelling allows to estimate the potential danger for glacial lake outburst floods (GLOFs). This paper presents a comprehensive approach by coupling of remote sensing, geomorphometric analyses aided with GIS modelling for the identification of potentially dangerous glacial lakes. We suggest a classification scheme based on an additive ratio scale in order to prioritise sites for detailed investigations. The identification and monitoring of glacial lakes was carried out semi-automatically using band ratioing and the normalised difference water index (NDWI) based on multi-temporal space imagery from the years 1971 to 2008 using Corona, ASTER and Landsat data. The results were manually edited when required. The probability of the growth of a glacial lake was estimated by analysing glacier changes, glacier motion and slope analysis. A permafrost model was developed based on geomorphometric parameters, solar radiation and regionalised temperature conditions which permitted to assess the influence of potential permafrost thawing. Finally, a GIS-based model was applied to simulate the possibly affected area of lake outbursts. The findings of this study indicate an increasing number and area of glacial lakes in the northern Tien Shan region. We identified several lakes with a medium to high potential for an outburst after a classification according to their outburst probability and their downstream impact. These lakes should be investigated more in detail