Abstract: Geospatial data base creation for landslide-hazard mapping is often an almost inhibitive activity. This has been the reason that for quite some time landslide-hazard analysis was modeled on the basis of spatially related factors. This paper presents the use of fuzzy logic to landslide-hazard analysis in the Penang Island, Malaysia, using remote sensing data and a geographic information system (GIS). To achieve the goal, a data-derived model (frequency ratio) and a knowledge-derived model (fuzzy operator) were combined for landslide-hazard analysis. Landslide locations within the study areas were identified by interpreting aerial photographs, satellite images and field surveys. The nine factors that influence landslide occurrence were extracted from the database and the frequency ratio coefficient for each factor was computed. Using the factors and the identified landslide, the fuzzy membership values were calculated. Then fuzzy algebraic operators were applied to the fuzzy membership values for landslide-hazard mapping. Finally, the produced map was verified by comparing with existing landslide locations for calculating prediction accuracy. Among the fuzzy operators, in the case in which the gamma operator (λâ=â0.8) showed the best accuracy (80%) while the case in which the fuzzy or operator was applied showed the worst accuracy (56%).
Abstract: Geomophological hazard assessment is an important component of natural hazard risk assessment. This paper presents GIS-based geomorphological hazard mapping in the Red Sea area between Safaga and Quseir, Egypt. This includes the integration of published geological, geomorphological, and other data into GIS, and generation of new map products, combining governmental concerns and legal restrictions. Detailed geomorphological hazard maps for flooding zones and earth movement potential, especially along the roads and railways, have been prepared. Further the paper illustrates the application of vulnerability maps dealing with the effect of hazard on urban areas, tourist villages, industrial facilities, quarries, and road networks. These maps can help to initiate appropriate measures to mitigate the probable hazards in the area.
Abstract: Object-based semi-automated segmentation and classification approaches have
gained importance in the analysis of remote sensing data over the last few years.
Particularly when it comes to operational processing of multi-seasonal input data,
independent and robust algorithms are needed. At the German Aerospace Center
(DLR) a new method for forest type classification has been developed, covering all
processing steps for object-based classification. An automatic adaptation of scenespecific
feature values for the classification is implemented, based on automated
extraction of feasible ground data. Therefore, no manual sampling of training data
is necessary. For classification of mixed forests on the basis of IKONOS data, a
special algorithm was developed that can be adapted to any kind of mixed forest
definition. Forest age classes are derived based on a digital surface model. The
developed method can be used for area-wide forest-type classification on the basis
of high and very high-resolution satellite data.
Abstract: The 3D surveying of two big cavities with very complex shapes in the Dachstein Southface Cave, Styria, Austria, serves as an example to demonstrate the efficiency of exact coordinate registration in caves by means of laser scanning. The surveyed cave is not open to the public and classified as difficult. The complicacy of a suggestive visualisation of such complex cavities is shown using the so-called Ramsau Dome as an example. Digital animations are considered the only possibility to adequately visualise such cave systems. During a surveying campaign of several days the Riegl Z-420i laser scanner worked reliably as data acquisition instrument despite the extreme conditions regarding temperature, air humidity and dirt. The generated point cloud models represent the presently best data bases for application modelling like for well discharges in karst hydrology and photo-realistic visualisations.
Abstract: This paper deals with landslide hazard analysis using Geographic Information System (GIS) and remote sensing data for Cameron Highland, Malaysia. Landslide locations were identified in the study area from interpretation of aerial photographs and field surveys. Topographical/geological data and satellite images were collected and processed using GIS and image processing tools. There are ten landslide inducing parameters which are considered for the landslide hazards. These parameters are topographic slope, aspect, curvature and distance from drainage, all derived from the topographic database; geology and distance from lineament, derived from the geologic database; landuse from Landsat satellite images; soil from the soil database; precipitation amount, derived from the rainfall database; and the vegetation index value from SPOT satellite images. Landslide hazard was analyzed using landslide-occurrence factors employing the logistic regression model. The results of the analysis were verified using the landslide location data and compared with logistic regression model. The accuracy of hazard map observed was 85.73%. The qualitative landslide hazard analysis was carried out using the logistic regression model by doing map overlay analysis in GIS environment. This information could be used to estimate the risk to population, property and existing infrastructure like transportation network.
Abstract: Failures of glacial lake dams can cause outburst floods and represents a serious hazard. The potential danger of outburst floods depends on various factors like the lake's area and volume, glacier change, morphometry of the glacier and its surrounding moraines and valley, and glacier velocity. Remote sensing offers an efficient tool for displacement calculations and risk assessment of the identification of potentially dangerous glacial lakes (PDGLs) and is especially helpful for remote mountainous areas. Not all important parameters can, however, be obtained using spaceborne imagery. Additional interpretation by an expert is required. ASTER data has a suitable accuracy to calculate surface velocity. Ikonos data offers more detail but requires more effort for rectification. All investigated debris-covered glacier tongues show areas with no or very slow movement rates. From 1962 to 2003 the number and area of glacial lakes increased, dominated by the occurrence and almost linear areal expansion of the moraine-dammed lakes, like the Imja Lake. Although the Imja Lake will probably still grow in the near future, the risk of an outburst flood (GLOF) is considered not higher than for other glacial lakes in the area. Potentially dangerous lakes and areas of lake development are identified. There is a high probability of further lake development at Khumbu Glacier, but a low one at Lhotse Glacier.
Abstract: Multitemporal space imagery from 1962 (Corona KH-4), 1992 (Landsat TM), 2001 and 2005 (Terra ASTER) was used to investigate the glacier changes in the Khumbu Himal, Nepal. The ice coverage in the investigation area decreased by about 5% between 1962 and 2005, with the highest retreat rates occurring between 1992 and 2001. The debris coverage increased concomitantly with the decrease in total glacier area. The clean-ice area decreased by >10%. Digital terrain model (DTM) generation from the early Corona KH-4 stereo data in this high-relief terrain is time-consuming, and the results still contain some elevation errors. However, these are minor in the snow-free areas with gentle slopes. Thus comparison of the surfaces of the debris-covered glacier tongues based on the Corona DTM and an ASTER DTM is feasible and shows the downwasting of the debris-covered glaciers. The highest downwasting rates, more than 20m (>0.5maâ1), can be found near the transition zone between the active and the stagnant glacier parts of the debris-covered glacier tongues. The downwasting is lower, but still evident, in the active ice areas and at the snout with thick debris cover. All investigated debriscovered glaciers in the study area show similar behaviour. The estimated volume loss for the investigated debris-covered glacier tongues is 0.19km³.
Abstract: Estimating urban green volume is getting more and more important within the frame of an ecologically orientated city planning and environmentally sustainable development. The first and the last pulse of airborne Light Detection and Ranging (LiDAR) data provide the basis for the estimation of green volume, but these optimal data are not always available, particularly for urban areas. That is why this paper deals with the question whether LiDAR data (last pulse only) that have not been taken during the vegetation period allow a sufficient estimation of the green volume. This paper sets up on previous results where LiDAR data have been compared to photogrammetrically determined vegetation height measurements. The subtraction of the laser-based Digital Terrain Model and Digital Surface Model in vegetated areas leads to a vast underestimation of green volume of up to 85%, which is mainly due to the standing deciduous trees with an underestimation of 90%. Starting from the existence of different laser response characteristics of various vegetation types, the relative point density and the normalized height of classified nonground points were analyzed in depth. The results show a good separation of different vegetation types. Furthermore, a pragmatic approach of reconstruction of the underestimated vegetation (mainly deciduous trees) is carried out by generating cylinders for the classified nonground points to compensate the volume loss. The point density of nonground points and the normalized height of the laser responses were used to regulate the adaptive cylinder construction based on fuzzy logic techniques. Using reference data, the accuracy could be estimated. In spite of the suboptimal LiDAR data, this paper leads to a sufficiently exact and efficient estimation of green volume compared to the costly conventional methods like field investigations. The method makes a contribution in the field of data improvement and is applicable to similar LiDAR data of other areas.
Abstract: In cooperation between remote sensing experts and cartographers interested in glaciology, new types of maps showing the glacier dynamics have been developed. The maps make use of the original phase gradient approach to glacier rheology modelling based on repeat-pass ERTS SAR interferograms. Careful map design and, in particular, colour assignment allow the visualisation of the glacier dynamics in its locally changing velocity with an estimated accuracy of approximately 2.0 cm per day. Two map derivates - a differential interferogram showing the glacier velocity and another product displaying the glacier strain rate - have been designed. Moreover, maps displaying the glacier marginal changes within the space of four years have been generated. The strain rate maps evidence that spots with high values frequently correspond with crevasse-prone areas which are even detectable under thick layers of snow. In this sense, the latter visualisations can be seen as maps of crevasse danger zones. The Svartisen in Norway and the Hintereis Glacier in Austria served as testbeds for the development of these different types of maps which are at the scales of 1:25 000, 1:50 000 and 1:100 000.
Abstract: Glaciers are sensitive climate indicators and therefore are effective
monitoring means for environmental and climatic changes.
Frequently remote sensing techniques are the only way to analyze
glaciers in remote mountains and they are certainly the only way to
monitor a large number of glaciers simultaneously. Although there
exist several glacier mapping methods, results still are often insufficient
for in-depth conclusions. In particular, this is true for debriscovered
glaciers. The Institute for Cartography of the Dresden
University of Technology, Germany, and the Department for
Geography of the University of Montana, Missoula, USA, are addressing
this issue by developing a methodology for accurate mapping of
debris-covered glaciers, focusing on the glaciers on the Nepalese side
of Mount Everest.
Abstract: Recently, use of remote sensing data for determining the orientation of stress has been demonstrated. The present study deals with the estimation of stress pattern in the part of the Himalayan region which shows the ongoing neo-tectonic activities. The study area falls into a tectonically active zone of the Central-Himalaya, with a complex geotectonic set-up confined by a number of faults. Efforts have been made to evaluate the technique as a fast algorithm for quick and time limited analysis of linear feature from which the orientation of the lineaments are estimated by using remote sensing data. Further, the estimation of stress and the lineament analysis have been used in mapping of landslide prone areas. Terrain information such as land cover, geology, lineament, faults, mega faults, geomorphology and drainage has been derived from the satellite imageries, and the existing thematic information has been updated to enable the quantification of landslide causative parameters. Spatial and temporal multi-layered information have been used for landslides hazard susceptibility analysis. The qualitative hazard analysis has been carried out using the map overlying techniques in GIS environment along the central part of Himalayan region. It has been observed that the high potential zones have been found to have very high lineament density, moderate to low drainage density and high slope areas of the terrain. On the basis of the geological and morphological analysis, it is further suggested that the combined impacts of the crushed nature of bed rock (due to the neo-tectonic activities), heavy rainfall and lack of vegetation cover cause persistent recurrence of landslides along this region. The role of earthquake on induction of landslides will be presented.
Abstract: Within the scope of a RussianGerman cooperation project under the guidance of the Commission on Planetary Cartography of the International Cartographic Association (ICA), a map of the moon has been produced. It is the third to be published within a series of multilingual shaded-relief maps of terrestrial planets and their moons. The surface is presented in two hemispheres at a scale of 1 : 12 800 000. Besides the relief representation, each of the planetary maps includes information on various parameters of the respective celestial body (astrophysical, geodetic, etc.), a list of Latin terms for relief feature designation and a list of relevant space missions to this planet or its moons. This information is printed on the back of the map in five languages, i.e. German, Russian, English, French and Spanish.
Abstract: Die High Resolution Stereo Camera (HRSC) an Bord der europäischen Raumsonde Mars Express ist die erste Kamera einer Planetenmission, die speziell für photogrammetrische und kartographische Zwecke entwickelt wurde. Seit Januar 2004 liefert die Kamera hochaufgelöste Bilddaten der Marsoberfläche in Stereo und in Farbe. Die Bilddaten bergen ein immenses Potenzial zur Ableitung präziser Digitaler Geländemodelle (DGMs) und farbiger Orthophotos sowie zur Herstellung topographischer und thematischer Karten und weiterer Produkte. Die Arbeitsgruppe für Photogrammetrie und Kartographie des internationalen HRSC-Forscherteams beschäftigt sich mit der systematischen Erstellung von Standardprodukten aus den Bilddaten und der Verfeinerung dieser Produkte mit dem Ziel, eine höchstmögliche Qualität zu erzielen. Dieser Beitrag beschreibt einige zur Verfeinerung geeignete Arbeitsschritte und illustriert den erreichten Stand anhand einer Reihe von Beispielen.
Abstract: The described activities aim at combining the potentials of photogrammetry, remote sensing, digital cartography and virtual reality/photorealism with the needs of modern spatial information systems for tourism and for alpinism in particular (the latter aspect is, however, not covered in the paper). Since for slopes steeper than 45°, a digital relief model in nadir projection cannot adequately depict the terrain even in low-angle views, digital Steep Slope Models (SSMs) with a rather vertical reference plane are desirable. This condition very much applies to the Eiger North Face which has been chosen as a testbed for the realisation of a virtual rock face and which shall later be embedded into a lower resolution synthetic landscape of the EigerâMoenchâJungfrau Region generated from a DTM and satellite imagery. Our âSSM approachâ seems justified by the fact that except for the visualisation, commercial software was used which is very limited both in DTM modelling and texture mapping. For the creation of the actual SSM, a pair of oblique coloured air photos has been used, resulting in both a digital face model of 3.7 m grid size and an orthophoto with a resolution of 0.25 m. To demonstrate the alpinistic potential of the product, climbing routes have been inserted into the face model, thus enabling even non-experienced individuals to enjoy the âvirtual reality conquestâ of the Eiger North Face and potential climbing candidates to prepare themselves for the actual âreal worldâ enterprise.
Abstract: Both, a geological GIS data base, a digital and an analog geological map of Central Chitral (Northern Pakistan), have been generated by
means of Arclnfo. The maps display a sound topographic basis, stratigraphic colour-coding and lithological raster signatures. Their production,
the benefits and shortcomings of the software used, and the geometric and thematic quality of the data sets are described. They represent
the first ones of the Western Himalayan System.
Abstract: Seit den siebziger Jahren des vergangenen Jahrhunderts hat sich im Gebiet südlich der Stadt Gadarif im Ostsudan, am Ostende der Sahelzone gelegen, nicht nur infolge des
Klimawandels, sondern auch aufgrund extremer agrarischer Nutzung eine signifikante
Veränderung der Vegetationsbedeckung ergeben. Stark reduzierte Bodenerträge führten in
den neunziger Jahren zu Stilllegungen von Ackerland. Mittels multitemporaler Satellitenbilddaten konnte die neuerliche Entwicklung der natürlichen Vegetationsverjüngung auf den Brachen nachgewiesen werden. Weiterer Schutz dieser Gebiete kann künftig die vollständige Regeneration der früheren Maximalvegetation eines
Savannenwaldes zwischen den Ãckern ermöglichen. Die festgestellten Landnutzungsbefunde werden mit den klimatischen Veränderungen in der östlichen
Sahelzone in Verbindung gebracht.
The period since the 1970s has seen significant changes to the vegetation cover in the region south of the city of Gadarif in East Sudan, at the eastern end of the Sahel, due to both the current climate change and extreme agricultural use. Seriously degraded harvests led to the abandoning of agricultural land in the 1990s. By means of multi-temporal satellite imagery, it has been possible to demonstrate the development of vegetation
renewal on such land. Further protection of the areas could permit complete future
regeneration of the previous maximum natural vegetation of a savannah between the agricultural fields. The ascertained land use changes are linked to the climatic changes in the Eastern Sahel.
Abstract: Glacier recession is a global phenomenon subject to climate change. This also applies to the Dachstein Massif in die Eastern Alps of Austria. Based on historical and recent maps, and moraine mapping the glacier states from the years 1850, 1915 and 2002 were used as input for for photorealistic reconstructions and visualizations of the respective glacier states. A detailed digital terrain model and aerial photographs (2003 â 2006) were provided by the Government of Styria and Joanneum Research Graz. By means of the software packages ERDAS Imagine 9.1, ESRI ArcGIS 9.2, 3D Nature Visual Nature Studio 3 (VNS), Digi-Art 3DZ Extreme and Avaron Tucan 7.2 the glacier conditions during the âLittle Ice Ageâ (+/- 1850) and the following two dates were reconstructed. Subsequently, several derivates of these data sets were generated.
First, three individual overflight simulations were computed, permitting to obtain a realistic impression of the Dachstein Massif and its glaciers in 1850, 1915 and 2002. As a second embodiment product, a fast-motion dynamic visualization of the glacier recession was generated which illustrates their decrease in thickness. Third, combining both the flip effect and the true-3D effect achievable by lenticular foils, were applied to produce a multitemporal autostereoscopic hardcopy display. Fourth, the overflight simulation data sets were used to generate stereo-films which could then be displayed on back-projection facilities using either passive polarization glasses or active shutter glasses.
Abstract: Many interactivity functions exist in explorative map applications. This chapter provides a typology of these functions with the aim to contribute towards a standardization of the variety of interactive visualization tools. The typology contains 8 types and around 70 particular interactivity functions and is based on an evaluation of existing divisions and categorizations of interactions. The standardization implies a facilitation of both the concept of interfaces and the assessment of realized interfaces. Using the developed structure, two existing applications are evaluated showing the usefulness of the typology.
Abstract: Gadarif region is one of the important mechanized rain-fed agricultural areas in Sudan and produces more than one-third of total national production of sorghum â the main food stuff in the country. Dryland farming throughout the region is practiced at various scales. The existing land use is characterized by complex vegetation covers and scattered distributed of small and large agricultural fields. Therefore it is difficult to delineate land cover features using only optical sensors. This study evaluates the potential of multi-sensor data for mapping of the cultivated area in a typical mechanized rain-fed agricultural environment in Ghadambaliya section of Gadarif region, Sudan. Multi-temporal images of Landsat (ETM+), ASTER, and TerraSAR-X data were used for the land use evaluation. For cultivated area classification, a pixel-based approach was applied to Landsat (ETM+) and ASTER data; while an object-based method was applied to TerraSAR-X data. Both supervised classification using Maximum Likelihood Classifier (MLC) and object-based image analysis were performed for land use analysis. The results show that, comprehensive information of land use provided by ASTER and Landsat (ETM+) images can be of great deal of help to identify the cultivated land areas. On the other hand a detailed land cover classes of the cultivated area was obtained from TerraSAR-X. The accuracy of the pixel-based and object-based classification methods was assessed using reference data sets derived from satellite data and ground truth field investigation data.
Abstract: In an introductory theoretical way the authors attempt to place cartography into the general context of sciences. Based on the traditional definition describing cartography as a science, technique and art, its defined scientific role in the development of geographic thinking is analyzed. This approach corresponds to the procedural method in epistemology. Cartography is, according to a general model in science, classified considering the fact whether its sources of origin of the concepts, its principles and postulates are genuine or derivatives from other disciplines. After comparative statements between Cartography and Geography an analysis of all environmental sciences with reference to the technologies use is carried out.
Abstract: Medium resolution SAR satellite data have been widely used for water and flood mapping in recent years. Since the
beginning of 2008 high resolution radar data with up to one meter pixel spacing of the TerraSAR-X satellite are
operationally available. The improved ground resolution of the system offers a high potential for water detection.
However, image analysis gets more challenging due to the large amount of image objects that are visible in the data.
Water body detection methods are reviewed with regard to their applicability for TerraSAR-X data. The concept for the
water body detection in the scope of the TanDEM-X mission is shown. Finally flood detection approaches for rapid
disaster mapping are presented in this paper along with a flood map example.
Abstract: Presently ASTER stereo-images represent an ideal tool to develop an automated way of mapping the ice extents of the actively flowing and the inactive glacier. Large areas of the glacier tongues are, however, heavily covered by supraglacial debris and this hampers the automated mapping of the actual ice snout by means of spaceborne imagery due to the similar spectral signal of the surrounding debris. The most significant features which distinguish the glaciers are the typical surface characteristics like their rough surface or âcryokarstâ and a number of ablation ponds. Looking in detail at these glaciers using multitemporal space imagery it is obvious that recent glacier shrinkage results in an increasing debris coverage and an increasing number and, hence, area of supra-glacial lakes. In addition, the surface, especially at the very distal part of the glacier, looks smoother and shows no significant indications for movement.
Combining thermal information from the ASTER sensor with various shape parameters de-rived from stereo-models, both the actual glacier beds and the marginal moraines can be outlined. Mainly due to the resolution of the ASTER DEM (30m) this concept is only promising for large glaciers such as the Khumbu Glacier. In future, when high resolution DEMs will be available, the accuracy will be sufficient for a fully automated glacier moni-toring, including smaller glaciers.
Abstract: For many years High Asia represents a research focus of the Institute for Cartography (IfC) of the Dresden University of Technology. The question regarding the reliability of ancient maps of this vast and remote region led to the production of an instructional film about the cartographic Oeuvre of the Swedish scholar, explorer and adventurer Sven Hedin. Hedin was the first European who advanced into the interior of the Taklamakan Desert and Tibet. His four expeditions carried out some 100 years ago did not only result in valuable carto-graphic material but also in general geographical, cultural and ethnological findings. His mappings were the most accurate cartographic sources of Inner Asia until the advent of spaceborne imagery. In cooperation with the Centre for Audio and Video Media (AVMZ) and the Centre for Information Technology Services and High Performance Computing (ZIH) of the TU Dresden the IfC produced a 35-minutes film about Hedin's map-making.
Abstract: The paper aims at determining land indices and suitability classes for spring wheat for intramontane continental Basins on example of Uimon Basin (Altai Republic, Russia). Star-ting-points approaches are: the Agricultural Soil Suitability Model âAlmagraâ (De la Rosa, 1992 and 2000) developed for mediterranean regions and a method specifically compiled by Burlakova (1988) for the Altai, based on weighted means of a factor set. 2) For comparison purpose, second, third and fourth version of the same model are developed using three differ-rent types of fuzzy logic approaches. Furthermore, the paper presents ideas how remote sen-sing might interact with the geo-information system (GIS) and modelling of soil and climatic conditions for land evaluation. A rating is classified using five suitability classes adopted from the FAO classification (1976). Social and economic factors are so far excluded, but can be added within a further phase of development.
Abstract: There is a global increase in the recognition of environmental, social and economic values of native vegetation, particularly in terms
of both sustainability of agricultural production and maintenance of natural resources. The rapid growth of the human population in
Sudan (2.6 % per year) stimulated the evolution of mechanized agriculture in the Gedarif Area from 500 ha in the 1940s to about 2.3
million ha in 2003. Nearly one third of Sorghum (Sorghum bicolor) and Sesame (Sasemum indicum) produced in Sudan is cultivated
in this area. Destruction of natural vegetation to provide agricultural land, associated with poor agricultural practices has resulted in a
continuous degradation of the natural resources. A significant amount of agricultural land is now abandoned. Within this context, the
objectives of the present study are to analyze the historical changes of natural vegetation due to agricultural expansion and to assess
the present condition of natural regeneration on the abandoned agricultural land.
Multi-temporal Landsat (MSS and ETM) data has been utilized to detect the historical vegetation changes using Change Vector
Analysis (CVA). Image transforms (NDVI and TCT), supervised classification and field data have been used to quantify different
land-use/land cover-classes and for assessing the present condition of the natural vegetation on abandoned agricultural land in the
study site. Field survey has been conducted using stratified random sampling. All sample plots have been registered using GPS.
Number and composition of trees/shrubs and above-ground herbaceous biomass were recorded. The field data has been combined
with the satellite imagery using regression technique.
The results demonstrate the capacity of the CVA to stratify different historical land-use/land-cover dynamics with a measurable
direction and magnitude. Results showed a fast process of deforestation within critical levels. The remaining natural vegetation of
2003 represented approximately one fifth of the total natural vegetation of 1972. Field data has proven to be important to increase
classification accuracy and to assess the vegetation attributes which otherwise could not be estimated using the Landsat imagery only.
Abstract: The Dresden University of Technology takes part in the scientific programme of the Mars Express Mission (MEX). The
MEX Group of the Institute for Cartography of the Dresden University of Technology envisages the further
development of true three-dimensional modelling techniques of remote sensing data for the cartographic 3D hardcopy
visualisation. The work contains three major parts: Geometric Modelling, Graphic Modelling and Cartographic
Modelling. Since the whole image coverage of Mars requires high computer memory resources, an optimal thinning of
the DTM is part of the tasks for the first milestone. Here, the determination of parametric surfaces contains the
transformation of a digital elevation model by means of B-Splines or NURBS (Non-Uniform Relational B-Splines).
This surface description allows a real three-dimensional management and modelling of terrain data (Solid Modelling)
and, foremost, the reduction of the image data in the texture maps. The transformation of digital 3D models into
adequate analogue viewable models shall be automated as far as possible. Finally, tools and methods for the
cartographic modelling have to be defined and implemented into the software. Here, the integration of de-shaded image
products is a prerequisite for the visualisation with changing illumination sources. 3D outputs in digital and analogue
form require an interface to existing modelling and output systems. Algorithms and methods which aim at the
production of high-quality lenticular foil maps have to be developed and tested.
Abstract: Within the last decade several studies using polarimetric SAR data for bio-/geo-physical feature extraction have been reported and have significantly improved the understanding of polarimetric scattering mechanisms. In a comparative view, the approach presented here, which is based on Shane Cloud's Decomposition Theorem, seems to be most promising: the Entropy H and <is proportional to> Angle Classification has been extended by using not only the parameters H and <is proportional to> but also the first eigenvalue λ1. A big advantage of this approach is the high correlation between its results and the physical properties of different landsurface materials, which makes this recently adapted method well-suited for both supervised and automated landcover classification. It is also most useful for the derivation of topographic as well as thematic map information, the scale naturally depending on the sensor's spatial resolution. The well-known DLR Oberpfaffenhofen study site in southern Germany served as a testbed for the exploitation of spaceborne SIR-C/X-SAR data and of L-band data from DLR's airborne experimental ESAR. For validation purposes the classification results have been high-precision geocoded and compared to both ground truth and recent map data, also superimposing the digital national topographic geodata of Germany, ATKIS. The classification proved to be of extraordinary accuracy, as far as can be judged by visual inspection. An exact quantification is underway. The approach presented is being further developed and will - in contrast to the flat test-site used so far - be applied to data flown by a new airborne SAR sensor over mountainous terrain at the northern rim of the Bavarian Alps. First results in this respect look very promising.
Abstract: Das Ergebnis kann sich sehen lassen: in diesem weltweit bislang einmaligen Projekt wurde die Höhle hochexakt vermessen, kartiert und als virtuelles Modell im Supercomputer des Uni-Rechenzentrums visualisiert. Zwei der VorstöÃe in die Tiefe wurden vom Filmteam des Audiovisuellen Medienzentrums begleitet. Nun ist die Vidoedokumentation fertiggestellt. Vermessung einer Finsternis ist ein Film, der alle Facetten der Höhlenforschung beleuchtet: die aufwendige Logistik, das mühsame Vordringen ins Höhleninnere, die zeitraubende Gewinnung der Messdaten, die Entbehrungen bei den mehrtägigen Aufenthalten unter Tage, aber auch faszinierende Naturgebilde wie beispielsweise die einzigartigen Hirschgeweih-Stalaktiten. Der Flug einer "virtuellen Fledermaus" durch das per Satellitendaten ins Gelände eingepasste digitale Höhlenmodell macht die Höhle zumindest optisch für jedermann zugänglich.
Abstract: Seit Jahrzehnten gibt es Bestrebungen, die Dachsteinsüdwandhöhle zu erforschen. Der Film zeigt, wie mit modernsten, laser- und computergestützten Methoden das Höhlensystem nunmehr hochexakt vermessen wird. Aus den gewonnenen Vermessungsdaten und Fotografien der Höhlenforscher erzeugen Kartografen und Software-Spezialisten ein wirklichkeitsnahes dreidimensionales Höhlenmodell. Damit wird es für einen grossen Kreis von Interessierten möglich, die Höhle âvirtuellâ zu besichtigen. Mit einem simulierten Flug aus dem Höhleninneren heraus und über die synthetische 3D-Landschaft des Dachsteingebirges endet der Film.
Abstract: Currently glaciers are undergoing considerable fluctuations in response to greenhouse gas-induced changes of the global temperature. Even at very short time-scales, regional climate changes are detectable at small tropical and subtropical glaciers acting as sensitive indicators of climate signals. Remote sensing studies and glaciological field investigations were carried out in the Nevado Ojos del Salado region in Chile â Argentina, situated in the southern Atacama high-Andes at a latitude of 27°S. The aim was to identify and address mountain glaciers in the south edge of the Arid Diagonal and to distinguish them from perennial snow cover. In situ field measurements indicate a glacial distribution of slope, cirque and niche glaciers, as well as glacierets between about 5300 and 6750 m. Optical remote sensing data of the Landsat TM (1986) and ASTER (2000) sensors with 30 m and 15 m resolution respectively were used to discriminate accumulation and ablation zones in the Nevado Ojos del Salado region. A supervised maximum likelihood classification was applied on a single band combination of the atmospheric reflectance band ratio TM4/5 (ASTER3/4), the Normalised Difference Vegetation Index, and the principal components PC2 to PC4. The total glacierised area in the study area is characterised by a considerable decrease of 40 % from 56.80 km² (1986) to 34.04 km² (2000). The shrinkage is related to a significant reduction of the ablation area from about 40.13 km² (1986) to 17.06 km² (2000), whereas the accumulation area remains nearly constant.
