Elevation data Photo Nordland South 2021 Part 4 of 5

Elevation data provides a detailed description of terrain and surface. The data are established as point clouds from airborne laser scanning or matching from aerial images. The point clouds have varying density (point/m²) for different purposes. From the point clouds, elevation models are generated on grid format of terrain (DTM) and surface (DOM).高程数据（Elevation data）可精细化刻画地形与地表的细节特征。此类数据可通过机载激光扫描（airborne laser scanning）生成点云（point clouds），或由航空影像（aerial images）匹配得到点云。针对不同应用需求，点云的密度（点/平方米）存在差异。基于上述点云，可生成针对地形（Digital Terrain Model，DTM）与地表（Digital Surface Model，DOM）的栅格格式高程模型。