Urban vegetation extraction from VHR (tri-)stereo imagery : a comparative study in two central European cities

The present study proposes a workflow to extract vegetation height for urban areas from Pléiades stereo and tri-stereo satellite imagery. The workflow was applied on a stereo image pair for Szeged, Hungary and on tri-stereo imagery for Salzburg, Austria. Digital surface models (DSMs) of the study areas were computed using the semi-global matching algorithm. Normalised digital surface models (nDSMs) were then generated. Objects of vegetation and non-vegetation were delineated based on the spectral information of the multispectral images by applying multi-resolution segmentation and support vector machine classifier. Mean object height values were then computed from the overlaid pixels of the nDSMs and assigned to the objects. Finally, the delineated vegetation was classified into six vegetation height classes based on their assigned height values by using hierarchical classification. The vegetation discrimination resulted in very high accuracy, while the vegetation height extraction was moderately accurate. The results of the vegetation height extraction provided a vertical stratification of the vegetation in the two study areas which is readily applicable for decision support purposes. The elaborated workflow will contribute to a green monitoring and valuation strategy and provide input data for an urban green accessibility study.DK W 1237N23(VLID)251709

Voranalysen von Sentinel-2-Zeitreihen als Basis für fernerkundungsgestützte Biotopkartierungen in der Alpinzone = Preliminary Analysis of Sentinel-2 Time Series for EO-based Biotope Mapping in the Alpine Zone

Aktuelle Satellitendaten, wie die europäischen Sentinel-2-Daten, können genutzt werden, um eine Erfassung von Lebensraum- und Biotoptypen im Hochgebirge zielgerichtet zu unterstützen. Der Beitrag diskutiert das generelle Potenzial von hoch aufgelösten, optischen Satellitendaten für ein intensives Monitoring mit häufig wiederholbaren Messungen und überregionaler Vergleichbarkeit. Erste Ergebnisse des Projekts EO4BTAlp zeigen die Eignung von Sentinel-2-Zeitreihen im Jahresgang, um sowohl Feldbegehungen besser zu planen als auch höchst aufgelöste Satellitendaten für Detailstudien zu akquirieren

Population estimation in urban areas based on "mixed/cross" stereo models

In the project X3D4Pop we investigate if "mixed" satellite image pairs acquired on two different dates can be used to calculate meaningful building heights in urban areas. Based on These results, the dependency of urban population estimation models on the availability and quality of 3D data is tested. Study areas are Port-au-Prince and Salzburg. The 3D-models are validated against LiDAR-derived elevation models, population numbers are compared with rastered population data from Statistik Austria. The project explores first steps towards an urban population estimation Service by remote sensing, for the humanitarian community

Generation of digital surface models in urban areas using triple-stereo imagery . GI_Forum|GI_Forum 2016, Volume 1 – open:spatial:interfaces|

Stereo or even triple-stereo satellite imagery of very high spatial resolution is a versatile source for many applications and analyses. The aim of this short paper is to demonstrate the level of accuracy that can be calculated for digital surface models using triple-stereo data in urban areas. Urban planners benefit from such results thanks to the fast processing time and low cost in comparison to other data, such as LiDAR data. In addition, the data obtained using stereo or triple-stereo technology simultaneously acquire the requisite spectral information. This study used semi-global matching (SGM), which runs a pixel-wise matching of two image pairs. SGM outputs a point cloud for each pair, which is used for the generation of digital surface models (DSMs). The result of the study is a DSM which can be used in urban areas for the estimation of urban volumes such as the vegetation volume or building cubature. Results are evaluated with respect to the overall accuracy, the number of errors, and missing values due to shadows or dark homogeneous areas

Generation of digital surface models in urban areas using triple-stereo imagery . GI_Forum|GI_Forum 2016, Volume 1 – open:spatial:interfaces|

Stereo or even triple-stereo satellite imagery of very high spatial resolution is a versatile source for many applications and analyses. The aim of this short paper is to demonstrate the level of accuracy that can be calculated for digital surface models using triple-stereo data in urban areas. Urban planners benefit from such results thanks to the fast processing time and low cost in comparison to other data, such as LiDAR data. In addition, the data obtained using stereo or triple-stereo technology simultaneously acquire the requisite spectral information. This study used semi-global matching (SGM), which runs a pixel-wise matching of two image pairs. SGM outputs a point cloud for each pair, which is used for the generation of digital surface models (DSMs). The result of the study is a DSM which can be used in urban areas for the estimation of urban volumes such as the vegetation volume or building cubature. Results are evaluated with respect to the overall accuracy, the number of errors, and missing values due to shadows or dark homogeneous areas

Generation of digital surface models in urban areas using triple-stereo imagery . GI_Forum|GI_Forum 2016, Volume 1 – open:spatial:interfaces|

Stereo or even triple-stereo satellite imagery of very high spatial resolution is a versatile source for many applications and analyses. The aim of this short paper is to demonstrate the level of accuracy that can be calculated for digital surface models using triple-stereo data in urban areas. Urban planners benefit from such results thanks to the fast processing time and low cost in comparison to other data, such as LiDAR data. In addition, the data obtained using stereo or triple-stereo technology simultaneously acquire the requisite spectral information. This study used semi-global matching (SGM), which runs a pixel-wise matching of two image pairs. SGM outputs a point cloud for each pair, which is used for the generation of digital surface models (DSMs). The result of the study is a DSM which can be used in urban areas for the estimation of urban volumes such as the vegetation volume or building cubature. Results are evaluated with respect to the overall accuracy, the number of errors, and missing values due to shadows or dark homogeneous areas

GI_Forum / Remote-Sensing Applications to Support Rehabilitation of Water Infrastructure in Lapilang, Nepal

(VLID)282620