LIDAR Composite DTM 2017 - 50cm

This dataset is no longer available on the Data Services Platform.
New version of the LIDAR Composite DSM data is available here:
https://environment.data.gov.uk/searchresults;query=lidar%20composite%202020;searchtype=All;page=1;pagesize=20;orderby=Relevancy

The LIDAR Composite DTM (Digital Terrain Model) is a raster elevation model covering areas of England at 50cm spatial resolution. Produced by the Environment Agency in 2017, this dataset is derived from a combination of our full time stamped archive, which has been merged and re-sampled to give the best possible coverage. Where repeat surveys have been undertaken the newest, best resolution data is used. The composite is updated on an annual basis to include the latest surveys.

The DTM (Digital Terrain Model) is produced from the last return LIDAR signal. We remove surface objects from the Digital Surface Model (DSM), using bespoke algorithms and manual editing of the data, to produce a terrain model of just the surface. Available to download as ASCII files in 2km grids, data is presented in metres, referenced to Ordinance Survey Newlyn, using the OSTN’15 transformation. All LIDAR data has a vertical accuracy of +/-15cm RMSE. A tinted shaded relief, which is an image showing what LIDAR looks like when loaded into specialist software, is also available as a WMS feed. You can also download survey index files which shows, for any location, what Time Stamped survey went into the production of the LIDAR composite.

Light Detection and Ranging (LIDAR) is an airborne mapping technique, which uses a laser to measure the distance between the aircraft and the ground. Up to 500,000 measurements per second are made of the ground, allowing highly detailed terrain models to be generated at spatial resolutions of between 25cm and 2 metres. The Environment Agency’s open data LIDAR archives includes the Point Cloud data, and derived raster surface models of survey specific areas and composites of the best data available in any location.

To find out more about LIDAR and the various surface models we produce please read our story map

This metadata record is for Approval for Access product AfA458. Attribution statement: (c) Environment Agency copyright and/or database right 2019. All rights reserved.
Attribution Statement: © Environment Agency copyright and/or database right 2019. All rights reserved.

本数据集已不再在数据服务平台上提供。新的激光雷达复合数字高程模型（DTM）数据版本现已在此处可用：[https://environment.data.gov.uk/searchresults;query=lidar%20composite%202020;searchtype=All;page=1;pagesize=20;orderby=Relevancy](https://environment.data.gov.uk/searchresults;query=lidar%20composite%202020;searchtype=All;page=1;pagesize=20;orderby=Relevancy)。该复合数字高程模型以50厘米的空间分辨率覆盖英格兰地区，由环境署于2017年制作。本数据集源于我们对全时间戳存档的整合与重采样，以提供最佳的覆盖范围。在重复测量时，使用最新、最高分辨率的资料。复合数据每年更新，以纳入最新的测量数据。

数字高程模型由最后返回的激光雷达信号生成。通过专有的算法和数据的手动编辑，我们移除了数字表面模型（DSM）中的地表物体，以生成仅包含地表的地面模型。数据以ASCII文件形式提供，按2公里网格下载，单位为米，参照新林测量局（Ordinance Survey Newlyn），使用OSTN’15转换。所有激光雷达数据具有垂直精度为±15厘米均方根误差（RMSE）。此外，还可提供彩色阴影图，这是一张显示激光雷达在专业软件中加载时的图像，作为WMS数据流提供。您还可以下载调查索引文件，该文件显示了任何位置用于激光雷达复合的特定时间戳调查。

激光雷达（Light Detection and Ranging）是一种航空测绘技术，利用激光测量飞机与地面之间的距离。每秒可进行高达500,000次的地面测量，从而在25厘米到2米的空间分辨率范围内生成高度详细的地面模型。环境署的公开数据激光雷达存档包括点云数据和特定区域和最佳数据的复合栅格表面模型。

欲了解更多关于激光雷达和我们所生产的各种表面模型的信息，请参阅我们的故事地图。

本元数据记录为访问批准产品AfA458。归属声明：（c）环境署版权和/或数据库权利2019。保留所有权利。归属声明：© 环境署版权和/或数据库权利2019。保留所有权利。