Available Data - Response of Flood Events to Land Use and Climate Change - page 121

Chapter 5
Available Data
5.1 Introduction
This chapter covers the available data and sources of the data and other infor-
mation which was applied in this research. All available data such as the digital
elevation model (DEM), aerial photos, GIS layers such as land use maps, soil map,
hydro maps, geological maps, and hydrometric and climatological data were
provided by Dr. Jean-Philippe Malet from the Meteorological Department in
Barcelonnette and Observatoire Multidisciplinaire des Instabilités de Versants'
(OMIV): [ 1 ]. The radar-derived DEM of 5 and 10 m resolutions was retrieved
from the OMIV coordinator, OSUG-LGIT, Maison des Géosciences in France.
5.2 Data Description
Aerial Photographs: Except for 1956 and 1995, all aerial photographs from 1974,
1982, 2000, and 2004 (Table 5.1 ) were orthorectified. The orthorectification
process for aerial photos from 1956 to 1995 was carried out as a project study by
Rainer Stumper, a Geography student at Vienna University. The sequence of the
photographs from 1995 consists of 45 images with a minimum scale of 1:28.000.
By a scan resolution of 600 ppi it represents a spatial resolution of at least 1.0 m
per pixel. The aerial triangulation was done by using the software ''ERDAS
Imagine 9.1—Leica Photogrammetrie Suite''. The camera parameters were set and
the images were initially arranged in their exterior orientation.
The correct arrangement of the flight plan was important for the iteration
progress, which will not calculate accurate orientation by wrong settings. To create
the geometric relation, 108 tie points and 34 GCPs were identified on the images
and the orthophotograph from 2004 respectively. Their adjustment and distribution
were chosen after the schema from the ERDAS manual [ 2 ]. The result of the
iteration was a total RMSE of 1.79 pixels. With this model the images were