3.2.3. Satellite imagery
Satellite images are those that have been taken from satellites.
Landsat (Fig. 6) is one of the longest running platforms for image acquisition
using the Thematic Mapper (TM) or the Enhanced Thematic Mapper (ETM) satellite
image acquisition systems (http://landsat.gsfc.nasa.gov/) which provide multispectral imagery for
the whole world (Campbell, 2002). Satellite imagery is often expensive to buy
as the equipment is difficult to operate and maintain, but conveniently,
Landsat and other satellite images can be added as raster layers directly into
the GIS interface.
Fig. 6. A section of the Swisstopo (2013) Landsat image (freely available from at http://www.swisstopo.admin.ch/internet/swisstopo/en/home/products/images/ortho/landsat.html) with a resolution of 25m, covering the study area of Fribourg, Switzerland. Reproduced with permission of Swisstopo (BA13016).