Navone, Stella Maris
The correlation value between principal components/radar/inverse fourier and
ground truth and IHS/radar indicates the efficiency of the different algorithm in differen-
tiation desertification degrees.
Table 3:Levels of deserfication map units according to the enhanced images and
to the field
None 0% 0% 0%
Slight 12,23% 20,88% 6,6%
Slight/mod 0% 0% 0%
Moderate 30,67% 26,55% 57,1%
Mod./ Sev. 27% 20,34% 5,78%
Severe 17,04% 23,88% 27,7%
Very Severe 12,05% 8,35% 2,75%
R:0,88 R:0,692
R2:0,82180203 R2:0,483078
Conclusions:
The whole valley of the Santa Maria river has been subjected to some degree of
dessertification.In fact, 70% the valley falls evenly either into moderate to severe or the severe
category.
The useful image obtained to identificate different desertification map units was principal
component transform with radar and reverse transform (figure 3). This product highlight
moderate to severe degree. The merge of optical and radar data convey both chemical and
physical information and could prove more useful than either image alone.
It is expected that on the basis of desertification indicators obtained from this
survey, together with the methodology developed, the early, quick and efficient detection
of different desertification levels and the monitoring thereof, will be possible. It will also
be possible to reinforce the gathering of data and of concrete experiences, with the
positive and negative aspects of the different actions carried out in the region in
connection with desertification.
Acknowledgements:
The authors are grateful to the Canadian International Development Agency
Which inside the GlobeSar program have covered the cost of the fields and training travel.
Radar data was supplied by GlobeSar program and Landsat Thematic mapper
images were provided by CONAE (Comision Nacional de Actividades Espaciales) y
Figure 7:Desertification degree (Field survey)
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 969
