A Digital Terrain Model (DTM) is typically used in applications such as environment planning, flood risk evaluation and building detection. A Digital Surface Model (DSM) is usually acquired by LASER scanning or from stereoscopic pairs of aerial or satellite images. By contrast, a direct DTM acquisition traditionally requires more effort on the terrain or for scene object classification and the ...

The goal of this study was to analyze the filtering performance of LiDAR data of an algorithm implemented by our group of research. The algorithm is completely automatic and needs only the raw data classified as first and last pulses. It was implemented in the open source software GRASS and it is composed of three functions that have to be launched in sequence: v.lidar.edgedetection, v.lidar.gr...

Abstract. Surface roughness influences the release of avalanches and dynamics rockfall, debris flow, but it is often not objectively implemented in natural hazard modelling. For two study areas, a treeline ecotone windthrow-disturbed forest landscape European Alps, we tested seven algorithms using photogrammetric digital surface model (DSM) with different resolutions (0.1, 0.5 1 m) moving-windo...

Thanks to the evolution of new sensors and the development of efficient algorithms, the automatic production of DSM (Digital Surface Models) and DTM (Digital Terrain Models) in urban areas has become possible. At SIRADEL, we have been interested in a new approach using external 3D vectors and a pair of aerial stereo images. In this paper, our method for computing DSM and DTM is briefly presente...

Original scientific paper In this work, an automated approach for building detection using airborne images and LIDAR data is presented. A combined approach of four methods achieved the best results, using slope-based DSM filtering as well as classification of multispectral images, elevation data and vertical LIDAR point density. The first variant of building detection is based on multispectral ...

Diierent dynamic subgrid scale models, viz. the dynamic model of Germano et al. are evaluated by means of a priori tests. Direct numerical simulation data for fully-developed turbulent and transitional incompressible ows are used. Low correlation is obtained between exact and modeled subgrid scale stresses with the DSM. Conversely, good agreement is found for both the DMM and the DTM, since tho...

In urban GIS and management, Digital surface model (DSM) can be used for generating object models. The preliminary step is to segment the interesting areas. In this paper, we present an integrated method of building extraction using transform from DSM to normal angles and watershed segmentation to the gradient of DSM. To remove the effect of the terrain shape to building detection, we firstly d...

Submetric satellite imagery (Pleiades, GeoEye) offers advantages for map update purposes, e.g. an interesting ground resolution, a good reactivity and the ability to capture wide areas. Experiments on the use of such stereoscopic images for 2D change detection among building objects of GIS topographic database are presented in this paper. Two approaches have been tested. The first one extracts ...

Smallholder tree plantations are expanding in the steepland tropics due to demand for timber and interest in ecosystem services, such as carbon storage. Financial mechanisms are developing to compensate vegetation carbon stores. However, measuring biomass—necessary for accessing carbon funds—at small scales is costly and time-intensive. Therefore, we test whether low-cost drones can accurately ...