REQUE ils
Fig. 6 Overlay LANDSAT MSS Imagery and
Physiographic Map by SPECK et al. (1982) Geometry
not corrected, scene approx. 50 km x 50 km, for
numbers and comment see text
50 km
i
[C
Fig. 7 Area Maquinchao-Jacobacci (Fig. 6) as
recorded by NOAA (March 9th, 1987), bands 1, 2,
9 used for colour output
155
It turns out that multispectral classification would
not allow to extract fully the information offered
by LANDSAT MSS imagery for desertification
monitoring. Interpretation of imagery by a skilled
expert based on ground truth seems to be the best
method for segmentation of object classes.
Small features may be very useful for the
desertification expert and serve as an important
indicator for degradation. This is studied in large scale
like explained in Fig. 6. However, the project has to
consider Patagonia as a whole.
Consequently, monitoring of desertification in Pa-
tagonia presents a lot of organisational challenges,
because it refers to a very large area while individual
plants may serve as indicators for the degradation
process. Therefore the procedure „from large to
small“ is applied: starting from intensively checked
areas (like Jacobacci-Maquincao) the knowledge
acquired there - including ground truth - is used
in the transects and from there interpolated for the
whole country. This process represents a particular
regionalisation scheme.