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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
Class D: Represents 17.20% of the total area. This class is
related with the surrounding relief to the Guadix basin. The
class has a mean height value of 1272m and its variability is
greater (coefficient of variation around 33%) due to the well
developed hydrological network (gullies). Nevertheless, the
directional variograms present a continuous and isotropic
behaviour at distances lower than 1.22. The variability is
slightly lower in E-W direction due to the foot of Sierra Nevada
range.
Class E: Represents 13.85% of the total area. This class is
related with the hillside of the surroundings relief. The class has
a mean height value of 1728m and present a considerable
variability (coefficient of variation around 27%). The
variograms present a small variability in NO°E and N45°E
directions according to the north hillside of Sierra Nevada.
Class F: Represents 8.52% of the total area. This class includes
high-terrain areas of the Sierra Nevada and Sierra de Baza
mountains. The class has a mean height value of 2018m and
presents a coefficient of variation of 22%. The directional
variograms presents a greater continuity in NO°E direction for
distances greater than 1000m.
Class G: Represent only 2.36% of the total area and it is related
with the highest areas of the zone (Sierra Nevada and Sierra de
Baza mountains peaks). The class has a mean height value of
2175m and present a coefficient of variation of 21% (similar
that the previous class). The directional variograms have a
similar behaviour has the corresponding ones of the Class F.
3.5 Geological interpretation
Classes D, E and F (light green, yellow and red colors in Figure
5) correspond with rocks which belong to the basement of the
basin (Alboran Domain and Sudiberian Domain). In classes A
and B (purple and blue colors) appear sedimentary rocks of the
Guadix basin. The present fluvial pattern, corresponding to
Guadalquivir river, can be identified in the Classes B and C
(blue and green colors). Areas classified as Class A (purple
colors) correspond to a glacis surface which represents the
termination of the endorheic infilling.
4. CONCLUSIONS
The proposed method for the morphological terrain
classification using statistical and geostatistical information
provides valuable information about the terrain. This
information is obtained from an objective procedure based in
the ISODATA non-supervised classification using multivariable
digital terrain model. The model is composed with a large
number of variables that reflect different characteristics of the
terrain (mean terrain height, variability, anisotropies, ...).
The used information in the classification process provides a
more robust classification that the usually applied based in a
small number of variables. The classical procedures are based
in a direct classification using in many times only one variable
(for example, heights or slopes).
The presented example shows a clear relationship between the
established classes and lithological units of the area, providing
additional statistical information very useful for the numerical
terrain characterization.
67
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ACKNOWLEDGEMENTS
The present study has been sponsored by the grant REN2001-
3378/RIES from the I--D-I program of the spanish Ministerio
de Ciencia y Tecnología, partially financed by FEDER funds of
the European Union.
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