Zwerchwand rockfall/topple and Stambach mud slide

GIS analysis

For GIS analysis different inputs where used:

First of all a digital elevation model was created from the isolines of the cartographic model. The morphometric aspects of a geomorphological research can be supported efficiently with the help of an optimised, true to scale digital elevation model. The quality of the digital elevation model is therefore of crucial importance. With the right choice of resolution and some additional structural steps during the DEM production, the output quality can be significantly increased. As it was impossible to gain a better resolution (than 10 - 15 m which is about the outermost resolution one can get from a cartographic model based on a map 1 : 50.0000) from the data provided another datasource - a topographic map especially created after the mudflow in 1982 in scale 1 : 1000 was manually digitized. Afterwards DEMs with 3 - 5 m resolution where created.

The DEMs where used to create some plots for interpretation of aspect, slope angle, curvature and flow accumulation.

 

   

Example of 15 m DEM calculated from the cartographic model - slope classification (violett, pink and red are slopes greater than 30 degrees, green means less than 10 degrees). Zwerchwand is nearly in the upper right corner.

More detailed and not yet smoothed DEM from map 1 : 1000 showing aspect. white areas are flat areas in the DEM due to calculation errors. A filter has to be applied to get rid of those errors and create a model that has a smoother (and a bit generalized) surface.

One of the final products of the GIS-work was a map created out of a combination of all input data (including field work, geology, ...) which shows the bedrock and substrate and all forms occuring in the area. The interpretation of the different elements should be done in combination with all other maps created during the investigation.

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