Collating New Zealand’s LiDAR Data

Author: Stephen Bensberg
Date: 8 March 2010

Tags: LiDAR, RADAR, digital elevation model, data

Over the last five to six years local and central government agencies have increasingly turned to remote sensing technologies such as Light Detection And Ranging (LiDAR) to obtain data about ground elevations.

In brief, LiDAR is very similar to RADAR (Radio Direction And Ranging) except that light waves - or more precisely, a laser - are used rather than radio waves. Typically the laser sensor is mounted on a plane (or satellite) and flown over the target area. The sensor emits a light beam and records the returned signals. The differences in each signal's return time, signal strength, and x, y, z co-ordinates are captured for later data processing.

Processed data from the return signals can be used to create Digital Elevation Models (DEM). These models provide a highly detailed and accurate picture of the height and shape of the land.

While LiDAR is currently the most commonly-used remote sensing tool, other light bands such as infra-red and multi-spectral are also available.

The data can be used in a range of projects, such as:

• determining the extent of floodplains
• monitoring coastal erosion
• predicting areas sensitive to sea level rise
• investigating the relationship between building insulation and heat loss
• carbon accounting through identifying the type of vegetation cover
• monitoring air quality.

The New Zealand Geospatial Office (NZGO) has started a project to collate a catalogue of all LiDAR data held by local and central government. We expect the catalogue will:

• improve the discovery of the data
• raise awareness about the wealth of data that has been collected
• support re-use of the data (once collected, the data can be used over and over in different projects and by different people)
• create opportunities for agencies to cooperate over new data purchases, and to improve compliance with technical guidelines and standards.

Next steps...

We are currently looking to publish a description (metadata) of the LiDAR data held throughout New Zealand, including the extent of LiDAR coverage.

The LiDAR inventory list is available from the NZGO and can be requested by contacting me on either my mobile (027-2499328) or via email (sbensberg@linz.govt.nz). Alternatively, you can contact us through this website.

We'd love to hear from you if you have any LiDAR data that could be included.

Stephen Bensberg

Project Manager Remote Sensing
New Zealand Geospatial Office