Vegetation Mapping

1:50 000 Vegetation Mapping Using Satellite Imagery

The photogrammetric capture of map data has been carried out by, what is now, the South Australian Department for Environment and Heritage since the 1960s. The 1:50,000 topographic map series required the photogrammetrist to capture drainage, fence lines, relief, cultural detail and vegetation stereoscopically.

Of these components, vegetation usually occupied up to half of the photogrammetrist’s time. For remote areas, it would take even longer. The most difficult sheets were those covering national and conservation parks which are complex mixtures of mallee, large trees and low shrubland. Remote sensing of vegetation was introduced to eliminate this very labour intensive activity.

Landsat TM or SPOT XS imagery was georectified to 1:50,000 map accuracy standards. Vegetation was delineated from the TM imagery through the application of an NDVI (normalised difference vegetation index), and a subsequent unsupervised classification. The benefits of using satellite imagery over more traditional photogrammetric methods include:

• Vegetation appears more variable and realistic.
• The cost is significantly lower due to the size of a Landsat TM image.
• Faster and more accurate representation of vegetation.

The images provided are samples from two different revisions of the same map sheet. The first is an example of the photogrammetric identification of vegetation, and the second displays vegetation delineated using Landsat TM imagery.

Click on the images for a more detailed view.
Vegetation information derived from an aerial photograph	Information derived from Landsat TM