METHODOLOGY FOR THE EXTRACTION OF HOMOLOGOUS POINTS FROM A DEM/DSM TO EVALUATE THE RELATIVE POSITIONAL ACCURACY

Abstract: This work presents a new methodology for extracting 3D homologous points from a DEM/DSM for relative evaluation of positional accuracies, from terrain features such as ridgelines and hydrography. Firstly, it extracts 3D intersection points between the linear features and then it performs a selection of these homologous points. A discussion regarding the spatial resolution effect of the DEM/DSM on the proposed methodology is carried out. As case study, the planimetric and altimetric positional accuracies evaluation of SRTM (X-band) and Aster GDEM (version 2) DSMs was conducted using, as reference, a DSM obtained via photogrammetry. The SRTM and Aster GDEM (version 2) DSMs showed similar classifications, that is, Class A for the altimetry and Class B for the planimetry at the 1:100,000 scale, according to the Brazilian technical standard of positional accuracy.

摘要：本研究提出一种全新方法，可从数字高程模型（Digital Elevation Model, DEM）/数字表面模型（Digital Surface Model, DSM）中提取三维同源点，用于基于山脊线、水文要素等地貌特征开展位置精度的相对评估。首先，该方法提取线性地物间的三维交点，随后对这些同源点进行筛选。此外，本文还探讨了DEM/DSM的空间分辨率对所提方法的影响。作为案例研究，本研究以摄影测量获取的DSM作为参考基准，对航天飞机雷达地形测绘任务（Shuttle Radar Topography Mission, SRTM）（X波段）与高级星载热发射与反射辐射计全球数字高程模型（Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model, Aster GDEM）（第2版）的DSM开展平面位置精度与高程位置精度评估。依据巴西位置精度技术标准，在1:10万比例尺下，SRTM与Aster GDEM（第2版）DSM的高程精度均为A级，平面精度均为B级，二者分类结果相近。