VEPs (Virtual Environmental Planning)

About - VEPs Technology - LiDAR

LiDAR (Light Detection and Ranging) Laserscanning

What is LiDAR?

3D city model from LiDAR dataLiDAR (Light Detection and Ranging) is a mapping technique that uses a laser scanner to measure the distance between it and an object. The laser scanner may be mounted in an aircraft to send out laser pulses to measure the distance between the aircraft and the ground in order to produce highly accurate terrain maps referred to as Digital Elevation Models (DEM).  These are used for a variety of purposes including assessing flood risk.

The LiDAR technique records the estimated height of the first and last surface that the laser pulse reflects off. The first reflection of the laser pulse received at the aircraft measures the distance between the aircraft and the tops of trees/buildings. The last reflection of the laser pulse records the distance between the aircraft and the Earth’s surface. A comparison of the images created from the first and last pulse can give an immediate impression of the terrain.

Laserscanning building facades

a ground-based laserscannerThe laserscanner may also be mounted on a tripod on the ground facing an object to provide a detailed map of that object including features such as the sides of a building and all the inherent detail of window frames and building textures.

LiDAR data has been increasingly used for developing three dimensional building data, as used in some of the VEPs demonstrations. Other methods of producing such 3D building data include satellite imagery, photogrammetry and Computer Aided Design (CAD) drawings.

Demonstrations

The following demonstrations show how the technology can be used to create simple three-dimensional views of existing buildings and terrain. In these examples, the Bristol Harbourside area has been chosen for illustrative purposes only. To view the examples, please view the requirements.

The first demonstration is of the 'raw' LiDAR data from an airborne laserscanner to create a simple image. Choose to view this demonstration as either:

The second demonstration shows outlines and average height information for buildings extruded from LiDAR data. (Note: this could also be done from building outlines derived from aerial photography or OS MasterMap outlines, combined with height data from LiDAR or alternative sources). Choose to view this demonstration as either:

In the final demonstration, some buildings have been manually edited to provide roof outlines and texture to help identify certain landmarks and features. This added information could be derived from photogrammetry or other roof outline data, such as the original height data or architectural CAD drawings. The issue of automatically extracting roof outlines from LiDAR data is on going area of research and development. Choose to view this demonstration as either:

Requirements

Further Information