DATE OSSIM PlugIn: a new open source tool for digital automatic terrain extraction

Nowadays High Resolution Satellite Imagery (HRSI) provides global coverage and allows for accurate and reliable terrain characterization and data extraction. In particular the Digital Surface Model (DSM) is one of the major outputs of the photogrammetric processing for satellite imagery and represents an important component of geospatial database. Consequently, over the years, a wide range of software (commercial and scientific) able to generate DSMs starting from HRSI has been developed. In the last two decades an increase of free and open source software for geospatial data processing has been witnessed. In this paper we present DATE – Digital Automatic Terrain Extractor – a new Free and Open Source Software for Geospatial (FOSS4G) developed in the framework of the 2014 Google Summer of Code program. DATE is conceived as an extension to OSSIM (Open Source Software Image Map), a suite of geospatial libraries and applications for imagery, maps, terrain and vector data processing, belonging to the wide OSGeo family. The tool is a free and open source plug-in able to perform a totally automatic DSMs generation chain starting from a high resolution satellite stereo-pair. In particular the tool can accommodate images acquired by the most common sensors (e.g GeoEye1, WordlView1-2, Quickbird, Pleiades). Its peculiarity consists in performing a “hybrid” processing chain based on both rigorous photogrammetric approach and Computer Vision techniques: there is a combination of OSSIM photogrammetric capabilities with the OpenCV library algorithms. Several tests have been performed in morphologically different areas and the DSM accuracy has been assessed using a high-resolution LiDAR DSM as a reference surface.