The usage of the historical cartographic datasets and the remote sensing data for the better understanding and mapping of the 2006 Danube floods in Romania

Abstract

The advantages brought by high resolution satellite data in activities related to flood mapping and flood monitoring are well know in the scientific community. The paper aims to prove that slighter older geospatial documents, such as historical maps, are also a valuable resource for cartographers and decision makers to achieve a better understanding of flood patterns and evolution. Some preparatory actions are needed in order to integrate the old maps into GIS environments for advanced analysis. This includes scanning, color enhancements, georeferencing, reprojection and metadata creation. To illustrate the process, the paper includes a real case scenario: the April 2006 Danube River flood. For one of the most affected sectors along the Danube, close to Rast village, three generations of historical maps (the Austrian 1:200 000 ‘degree maps’, the Romanian 1:20 000 ‘Lambert-Cholesky’ maps and the Soviet Union 1:100 000 ‘Gauss-Krüger’ maps) were processed and included in a large repository. At any time, the maps can be identified and accessed through open standard protocols like CSW and WMS. In this way, we were able to integrate and analyze the flood water masks, extracted from satellite data, along with the historical data sets. The results were very promising. It was possible to understand some flood patterns and to clearly demonstrate that, after the dike failure, the water filled up an area which in the past, before river regulation, was the natural Danube floodplain.