The investigation is based on GIS landform parameterization based on high resolution DEM, geophysical surveys and geological or geoarchaeological documentation. This article presents a method to use and link multiple sources of spatial information for determining boundaries of natural landform units in relatively flat (low relief gradients) urban areas, heavily altered by human activities.
In addition, the analysis of terrain morphology in urban areas based on DEMs are rarely supported by results of other investigations. Unfortunately, DEM analysis for flat, urbanized areas causes many errors associated with a model's accuracy, impact of land cover, existence of buildings and artificial transformations of ground surface (S ithole and V osselman 2004 B onk 2007 L iu 2008 R euter et al. These studies are greatly supported by digital elevation models (DEMs) and geophysical methods of ground penetration (K ampke 1999 C hallis 2006 P apadopoulos et al. Such difficulties accompany detailed geomorphological studies conducted during archaeological works (K vamme 2006). This often prevents an unequivocal identification of initial landforms and the correct analysis of the local palaeogeographic development. As a result, the natural land configuration, especially in lowland areas, is obscured and hard to identify. Geomorphological studies in urban areas are difficult to carry out due to dense development and artificial transformations of natural surfaces involving, among others, the formation of man-made ground and modifications of the drainage system (R osenbaum et al. The geophysical survey is useful to identify buried morphological edges and older relief elements in open areas. Finally, we argue that although high resolution DEM and derivate land-surface parameters are very useful in terrain analysis, places with thick man-made ground or strongly levelled areas must be recognized by geoarchaeological excavations or geological bore holes. As a result, a map of the main landforms of Wrocław is presented. Additionally, five typical sequences of man-made ground present within the perimeter of the city were distinguished. To this end, geophysical measurements were conducted using the Two-Dimensional Electrical Resistivity Tomography method. The study also involved determining morphological edges and measurements of the meanders of the Odra, as well as expanding information on the spatial distribution of alluvia and the structure of slope breaks. To this end geomorphometric studies were conducted with the use of digital elevation models (DEMs) based on LiDAR scanning and derivated land-surface parameters-SAGA Wetness Index, Channel Network Base Level and Altitude above Channel Network.
The city of Wrocław in Central Europe serves as an example. The main aim is to identify to what extent these complementary sources of data and the proposed method can be used in such a specific environment to reconstruct natural, buried terrain morphology. The paper presents a method of using and linking these sources of spatial information about landforms in such areas. Geophysical methods are also becoming increasingly popular in background studies. Lately, data from light detection and ranging (LiDAR) have become a valuable source of information on urban land configuration. Accordingly, archaeological works in cities, which supply knowledge on settlement conditions, are usually accompanied by geological and geomophological research. In urbanized areas, particularly in lowland terrains and floors of large river valleys, the natural land configuration is often hard to recognize due to a long history of human activity.
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