National LIDAR Programme

The Environment Agency National LIDAR Programme aims to provide accurate elevation data at 1m spatial resolution for all of England by 2021. The country has been divided into approximately 230 logical blocks with survey starting in November 2016. Surveys are undertaken during winter months (approximately November to April each year) and published through the DEFRA Data Services Portal each November.

To find out more about our current survey plans and historic capture visit: https://environment.maps.arcgis.com/apps/webappviewer/index.html?id=11a8edc1c1d341379c857bf3d3806e4b

LIDAR is an airborne mapping technique which accurately measures the height of the terrain and surface objects on the ground, through the use of a scanning laser that measures the distance between the aircraft and the ground. From this remote sensing technique we produce a number of products available to download:

Point Cloud(s) The Point Cloud are the discrete LIDAR returns that are used in the creation of the surface models. Supplied in *.laz format they an automated routine assigns a classification code to each laser pulse to distinguish between ground and surface objects.

Digital Surface Model(s) (DSM) The Digital Surface Model is created from the last or only LIDAR pulse returned to the sensor and contains all ground and surface objects.

Digital Terrain Model(s) (DTM) The Digital Terrain Model is created from the last return LIDAR pulse classified as ground, filtering out surface objects. Manual filtering is undertaken on the DTM to improve the automated classification routines to produce a most likely ground surface model. Areas of no data, such as water bodies, are also filled to ensure there are no gaps in the model.

First Return Digital Surface Model(s) (FZ DSM) The First Return Digital Surface Model is created from the either the first or only LIDAR pulse returned to the sensor and contains all ground and surface objects. It is more likely to return elevations from the top or near top of trees and the edges of buildings. It can often be used in canopy height modelling and production of building outlines.

Intensity Surface Model(s) (Int DSM) Intensity is a measure of the amount of laser light from each laser pulse reflecting from an object. This reflectivity is a function of the near infrared wavelength used and varies with the composition of the surface object reflecting the return and angle of incidence.The intensity surface model produces a grayscale image where darker surfaces such as roads reflect less light than other surfaces such as vegetation.

All products are available in 5km tiles aligned to the ordnance survey grid. The tiles are named by the unique survey id, OS grid reference and the first and last survey date of the survey id (P_XXXXX_OSOSOS_SDFLOWN_EDFLOWN.). The surface models are available in GeoTiff raster format whilst the point cloud is available in .laz. An index catalogue is also available with provides survey specific information about each tile.

To find our more about LIDAR data and the 1m full coverage programme please visit: https://arcg.is/05Xq4z Attribution statement: © Environment Agency copyright and/or database right 2015. All rights reserved.