Digital elevation model Hamburg DGM 25

Derived, comprehensive digital terrain model with a grid width of 25 meters based on the DGM1. For the area of the Free and Hanseatic City of Hamburg (excluding the area of the Hamburg Wadden Sea), a laser scan (airborne laser scanning) was carried out in 2020. The data are available in position status 310 (ETRS89/UTM), with elevation data above normal altitude zero (NHN), according to DE_DHHN2016_NH.

The accuracy of a single measuring point in clearly defined areas, such as on road surfaces, is approx. ± 255 cm. In areas of shading (bridges), vegetation, especially areas in forest and shrub areas and on steeply inclined terrain, the accuracy is lower.

By default, the LGV offers the following grid widths: DGM 1 (grid width 1m), DGM 10 (grid width 10m), DGM 25 (grid width 25m). An annual update of this data is carried out by aerial surveys.

In addition to the pure provision of height information as a regular grid, the data is also provided as a service in a triangular mesh (TIN). Data exchange with 2D and 3D CAD systems is ensured. As a further service, contour lines and profiles can be derived, for example, or volumes and inclinations can be calculated. By integrating further geobase and technical data (vector and grid data), further services can be derived, e.g. for the areas of water management, civil engineering, environment and urban planning as well as energy supply for large and small-scale applications.

本数据集为基于DGM1衍生的全覆盖数字地形模型，网格分辨率为25米。针对自由汉萨汉堡市辖区（汉堡瓦登海区域除外），项目组于2020年开展了机载激光扫描作业。该数据采用ETRS89/UTM坐标系，位置状态编码为310，高程基准采用DE_DHHN2016_NH规定的正常高基准（NHN）。

在路面等明确划定区域内，单个测点的精度约为±255厘米；而在遮蔽区域（如桥梁下方）、植被覆盖区域（尤其是森林与灌丛区域）以及陡坡地形中，数据精度会有所下降。

LGV默认提供以下网格分辨率的产品：DGM 1（网格分辨率1米）、DGM 10（网格分辨率10米）以及DGM 25（网格分辨率25米）。该数据集每年通过航空测量进行更新。

除了提供常规格网形式的高程信息外，本数据集还以不规则三角网（Triangulated Irregular Network, TIN）服务形式对外提供。可保障与二维、三维计算机辅助设计（Computer Aided Design, CAD）系统的数据交互交换。此外，该服务还支持衍生多项增值功能，例如可生成等高线与剖面、计算体积与坡度等。通过集成其他地理基础与技术数据（矢量与格网数据），还可拓展出更多应用场景，服务于水资源管理、土木工程、环境保护、城市规划以及大中小型规模的能源供应相关业务。