Ground surface elevation information represented as contour lines on a map is the most well known form of Elevation Data. Contours before the advent of LiDAR were obtained photogrammetrically from stereo imagery created from the aerial photography. Contour information captured this way was adequate for mapping but with newer LiDAR technology it has become unsuitable for high-end ground surface analysis, mapping, and accurate planning.
LiDAR surface model Southern Outlet, Hobart
Remote sensing technologies are providing new methods for capturing ground elevation data. Of these systems airborne LiDAR is now used primarily to provide high resolution data at an accuracy previously unattainable. LiDAR is able to penetrate all but the densest vegetation canopy. LiDAR stands for Light Detection And Ranging and in simple terms works by pointing a laser at a surface and measuring the time it takes for the light to return.
Radar is more suited to quick acquisition of large areas and satellites, as well as aircraft, can be used as the platform. It has the ability to penetrate cloud but struggles to penetrate vegetation cover due to the non-vertical nature of the radar beam.
Point Cloud Elevantion Data - Tamar Valley
Point Cloud elevation data is a by-product of imagery capture. Stereoscopic digital imagery enables each imagery pixel to not only have a horizontal position assigned, but also a vertical value. As the Point Cloud data is derived from imagery, any object or vegetation obscuring the ground will cause a problem for identifying the ground height at that point. It has a very high point density and is best suited to small open areas of capture.
Apart from 10 metre and 5 metre contour data and the 25 m DEM, all the elevation data available from this department is LiDAR derived covering over 60% of Tasmania.
An index of the LiDAR coverage of Tasmania is available on LISTmap. Please note that the index only indicates general coverage areas and not exact coverage.
Significant sections of the LiDAR data is owned by other organisations and has been provided to Land Tasmania to make available to all at no cost. All Tasmanian LiDAR data in the form of LAS files provided to Land Tasmania can be accessed via the national web service. To access the free data go to ICSM Elvis elevation.fsdf.org.au
For any other elevation information please contact Land Tasmania.