Altitude data Frosta Levanger 2011

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).

高程数据可对地形与地表进行精细化描述。此类数据通过机载激光扫描或航空影像匹配的方式构建为点云（point cloud）。
此类点云的点密度（point/m²）因应用需求不同而存在差异。
基于该类点云，可生成栅格格式的地形高程模型（DTM，Digital Terrain Model）与地表高程模型（DOM，Digital Surface Model）。