Height data Holmestrand 2008

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）可对地形与地表进行精细化描述。该类数据可通过机载激光扫描（airborne laser scanning）生成点云（point clouds），或通过航空影像（aerial images）匹配得到点云。针对不同应用需求，点云的点密度（单位：点/平方米）存在差异。 基于上述点云，可生成地形（DTM, 数字地形模型 Digital Terrain Model）与地表（DOM, 数字地表模型 Digital Surface Model）的栅格格式高程模型。