DOI: 10.26650/ijegeo.1957243 ISSN: 2148-9173

Impact of Stereo Geometry on DSM/DTM Accuracy from Göktürk-2b Imagery Using Agisoft Metashape Software Package

Hasan Abali, Gürcan Büyüksalih, Cem Gazioğlu
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This study investigates the geometric accuracy of Digital Surface Model (DSM) and Digital Terrain Model (DTM) generation from Göktürk-2B stereo and triplet satellite imagery using the Agisoft Metashape software package, quantitatively demonstrating the effects of stereo geometry and statistical filtering strategies on elevation model accuracy. In this context, especially, Rational Polynomial Coefficient (RPC)-based solutions, Ground Control Point (GCP)-supported optimization, and stereo/triplet image geometries on height model generation were analyzed in detail. In the application conducted over the Ankara Kahramankazan region, Göktürk-2B data with different acquisition angles was used, and the produced models were tested against the reference elevation model of the test area. This research demonstrates the usability of Turkish Göktürk-2B satellite data in high-resolution photogrammetric production processes through numerical error metrics. In the stereo-image processing, error discrepancies at control points resulted in an RMSE value of approximately 8.64 m for the DTM. In the DSM analyses, the geometric accuracy after filtering improved to 6.09 m. In the triplet (three-image) model, the overall accuracy was calculated as approximately 8.60 m after removing gross errors. Regional analyses showed that land cover type had a decisive effect on the accuracy. At ground control points (GCPs), RMSE values of 3.12 and 4.09 m were obtained by stereo and triplet image configurations respectively. These findings demonstrated that Göktürk-2B data can be used for reliable elevation model generation with appropriate control point distribution and statistical filtering.

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