Contours

EA LiDAR 2D and 3D Contours

The source data for the EA LiDAR contours has an accuracy of +/-5cm to 15cm, with the spatial resolutions ranging from 25cm to 2 metres. The dataset has been developed to show a 'bare earth' Digital Terrain Models (DTM). Contours are supplied at 0.5m intervals.

Contours are labelled and can either be taken as 2D (suitable for 2D CAD applications) or 3D.

Download EA LiDAR DSM Sample data

DSM 2D DWG Sample

DSM 3D DWG Sample

Download EA LiDAR DTM Sample data

DTM 2D DWG Sample

DTM 3D DWG Sample

NEXTMAP 5m DTM & DSM RADAR Contours

The source data for Nextmap 5m Contours is derived from NEXTMAP height data elevation points captured at every 5m.

For the DTM, the ground surface objects have been processed and removed to give a representation of the bare earth at an accuracy of +/- 1m RSME.

For the DSM any object large enough to be resolved will be represented in the data e.g buildings, vegetation and roads, as well as natural terrain features. Stated accuracy for this data +/- 2m RSME.

Contours are supplied at 0.5m intervals and labelled and can either be taken as 2D (suitable for 2D CAD applications) or 3D.

Download NEXTMAP DSM Sample data

DSM 2D DWG Sample

DSM 3D DWG Sample

Download NEXTMAP DTM Sample data

DTM 3D DWG Sample

OS Land-Form PROFILE Contours

Ordnance Survey's Land-Form PROFILE contour data is a data set representing the physical shape of the real world within Great Britain. Contained within this data set are height contours, and high and low water marks. Contour data has been captured from Ordnance Survey's 1:10 000 scale mapping.

Download sample data

OS Land-Form Profile DWG Contour Sample

OS Land-Form PANORAMA Contours

Like the OS PROFILE product (Ordnance Survey Land-Form PROFILE Contour Data), the OS PANORAMA product is a dataset representing the physical shape of the real world, and contains contour data. PANORAMA contour features are at 10 m elevation intervals (compared to 5m elevation intervals in the OS PROFILE product)

The accuracy of digital contours is typically better than 3 m (root mean square error (RMSE)). These refer to the differences between the contour height recorded on the map and the measured height (above mean sea level) at the points on the ground represented by that contour.

Download sample data

OS Land-Form Panorama DWG Contour Sample

Understanding Contour Data Collection

Photogrammetry
This is the practice of obtaining information, about physical objects, including height values, through the process of recording, measuring, and interpreting photographic images. Photogrammetry has been included within some LiDAR datasets as it can prove more reliable areas with rapid changes in terrain.

Topographical Survey
GPS survey and in the past, surveys levelled to the national benchmark network have been included in some datasets. However, due to the high cost of collecting data in this way, survey data has not been widely used to collect and produce commercially available datasets and is primarily used to verify other capture methods.