In order to obtain DTM(Digital Terrain Model),which is the principal work for data processing in various engineering on ground,some study is carried out on site,but a majority of DTM results from photogrammetry.

• 为了获得各种地面工程数据管理的基础,建立DTM(数字地面模型)是一项主要工作,多数DTM来源于摄影测量的成果。