LIDAR Composite First Return Digital Surface Model (FZ_DSM) - 1m

The LIDAR Composite First Return DSM (Digital Surface Model) is a raster elevation model covering ~99% of England at 1m spatial resolution. The first return DSM is produced from the first or only laser pulse returned to the sensor and includes heights of objects, such as vehicles, buildings and vegetation, as well as the terrain surface where the first or only return was the ground.

Produced by the Environment Agency in 2022, the first return DSM is derived from data captured as part of our national LIDAR programme between 11 November 2016 and 5th May 2022. This programme divided England into ~300 blocks for survey over continuous winters from 2016 onwards. These surveys are merged together to create the first return LIDAR composite using a feathering technique along the overlaps to remove any small differences in elevation between surveys. Please refer to the metadata index catalgoues which show for any location which survey was used in the production of the LIDAR composite.

The first return DSM will not match in coverage or extent of the LIDAR composite last return digital surface model (LZ_DSM) as the last return DSM composite is produced from both the national LIDAR programme and Timeseries surveys.

The data is available to download as GeoTiff rasters in 5km tiles aligned to the OS National grid. The data is presented in metres, referenced to Ordinance Survey Newlyn and using the OSTN’15 transformation method. All individual LIDAR surveys going into the production of the composite had a vertical accuracy of +/-15cm RMSE. Attribution statement: © Environment Agency copyright and/or database right 2022. All rights reserved.

该激光雷达综合首次回波数字地面模型（Digital Surface Model）为英格兰约99%的区域提供了1米空间分辨率的栅格高程模型。首次回波数字地面模型由传感器接收到的首次或唯一激光脉冲产生，包括车辆、建筑物、植被等物体的海拔高度，以及首次或唯一回波为地面的地形表面。该模型由环境局于2022年制作，其首次回波数字地面模型源自2016年11月11日至2022年5月5日作为国家激光雷达计划一部分所采集的数据。自2016年起，该计划将英格兰划分为约300个区块，以连续冬季进行测绘。这些测绘数据通过重叠区域采用羽化技术合并，以消除不同测绘之间的微小高程差异，从而创建首次回波激光雷达综合模型。请参考元数据索引目录，了解任何位置的激光雷达综合模型制作所使用的测绘数据。首次回波数字地面模型在覆盖范围或范围上不会与激光雷达综合模型最后一次回波数字地面模型（LZ_DSM）相匹配，因为最后一次回波数字地面模型综合是由国家激光雷达计划和时序调查共同产生的。数据可作为GeoTiff栅格以5公里瓦片形式下载，并按OS国家网格对齐。数据以米为单位表示，参照新林测量局（Ordinance Survey Newlyn），并采用OSTN’15转换方法。所有用于综合模型生产的单个激光雷达测绘数据均具有±15厘米均方根误差（RMSE）的垂直精度。版权声明：©环境局版权和/或数据库权利2022。版权所有。