Multitemporal Digital Elevation Models (DEMs) obtained by different surveying techniques and registered in the same reference system can be compared, leading to an integrated approach for studying Earth surface deformations. Moreover, the application of Geographic Information System (GIS) softwares for DEMs spatial analysis represents a powerful tool for obtaining significant morphometric parameters for geomorphological researches. Digital photogrammetric techniques, providing measurement of shape, position and dimension of objects on a surface from stereo images, combined with surveying of control points can generate regular spaced grid DEMs. Global Positioning System (GPS) kinematic surveys, which allow the description of the ground surface by coordinates measurements of points distributed on a high density irregular grid in a short time period, can also be used for DEMs production. A combination of digital photogrammetry and GPS techniques has been applied to generate Digital Elevation Models of a test area (hydrographic basin affected by landslides) extending for about 2,5 square kilometres and located 40 km South of Bologna, Italy, on the western slope of the Reno River Valley. DEMs accuracies, strictly related to the adopted surveying method, to the operative working conditions and to the morphological features of the study area, have been estimated. Comparisons of models related to 1976, 1993 and 2003 have allowed to evaluate variations of surface features. Spatial analysis procedures have been applied to 1976 and 2003 Digital Elevation Models, after appropriate filtering of data, in order to derive morphometric parameters for the whole of basin, including elevation, slope angle, slope aspect, relative elevation, slope curvature (plan and profile). Results, both for landslide areas and non-landslide areas, have been summarized in thematic maps. Final data have been output in three-dimensional (3D) interactive models, also rendered as multi-angle images, to provide an innovative medium for an immediate approach and interpretation of complex information
Digital Elevation Models and spatial analysis techniques in landscape evolution studies
FABRIS, MASSIMO;
2004
Abstract
Multitemporal Digital Elevation Models (DEMs) obtained by different surveying techniques and registered in the same reference system can be compared, leading to an integrated approach for studying Earth surface deformations. Moreover, the application of Geographic Information System (GIS) softwares for DEMs spatial analysis represents a powerful tool for obtaining significant morphometric parameters for geomorphological researches. Digital photogrammetric techniques, providing measurement of shape, position and dimension of objects on a surface from stereo images, combined with surveying of control points can generate regular spaced grid DEMs. Global Positioning System (GPS) kinematic surveys, which allow the description of the ground surface by coordinates measurements of points distributed on a high density irregular grid in a short time period, can also be used for DEMs production. A combination of digital photogrammetry and GPS techniques has been applied to generate Digital Elevation Models of a test area (hydrographic basin affected by landslides) extending for about 2,5 square kilometres and located 40 km South of Bologna, Italy, on the western slope of the Reno River Valley. DEMs accuracies, strictly related to the adopted surveying method, to the operative working conditions and to the morphological features of the study area, have been estimated. Comparisons of models related to 1976, 1993 and 2003 have allowed to evaluate variations of surface features. Spatial analysis procedures have been applied to 1976 and 2003 Digital Elevation Models, after appropriate filtering of data, in order to derive morphometric parameters for the whole of basin, including elevation, slope angle, slope aspect, relative elevation, slope curvature (plan and profile). Results, both for landslide areas and non-landslide areas, have been summarized in thematic maps. Final data have been output in three-dimensional (3D) interactive models, also rendered as multi-angle images, to provide an innovative medium for an immediate approach and interpretation of complex information
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