Remote Sensing: Groot Derm - Yellow Dune

Explanations for ETM-subsets

What kind of information is displayed?

This image is a subset of a Landsat 7 ETM+ image, covering a size of about 30 km by 25 km, which was acquired during the rainy season. It is visualized as a so-called false colour composite. On the Red, Green and Blue channels the spectral bands 4: NIR (near Infrared), 5: MIR1 (Mid Infrared 1) and 3: visible red of the Landsat ETM+ sensor are displayed (RGB: 4-5-3).This band combination suits best for a detailed visualization of different land cover properties. Due to that, the displayed colours are not natural.



In the displayed image the BIOTA observatory is given as a dotted rectangular box of 1km x 1km extension. 

 View Observatory

Groot Derm - Yellow Dune 

 WRS2 Path-Row


 Acquisition Date


 Image Details

The observatory (black rectangle) is located near the Orange River estuary. The vegetation in the sandy desert region is very sparse, as indicated by the bright colours. Yellow dune structures of about 3 m height (grey in this image) are crossing the observatory in North-South direction. Intense red and green circular structures indicate agriculture fields along the river course. 

In general, the colours refer to the following land cover types:

  • Dark Blue: Water bodies, dams and lakes without Algae.

  • Light Blue: in populated places mainly buildings, outside of towns mainly rocks, and very sparsely vegetated soils.

  • Red: Very dense and vital vegetation like bush thickets, forests or planted fields, in towns: gardens.

  • Green: "middle dense" or less vital vegetation, like grass savanna (light green) and dry bush (dark green).

  • White: bare soil or sparsely vegetated areas, independently from the natural soil colour, also gravel roads and pads.

  • Intermediate colours are representing mixed pixels with information of several land cover types.

E-Mail to Manfred Keil (subproject leader)