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| Titel |
Hydrological landscape classification based on Digital Elevation Models and orthophotos |
| VerfasserIn |
Ino Papageorgaki, Ioannis Nalbantis |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250080937
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| Zusammenfassung |
| Landscape classification is carried out, which focuses on the identification of areas that are
distinct with respect to the predominant runoff generating mechanism. Three criteria are used
for classification, which are calculated from ground elevation information in the form of a
Digital Elevation Model (DEM). These are: the index known as HAND (Height Above the
Nearest Drainage), the ground slope and the distance from the nearest drain or branch of the
hydrographic network, considered along the flow direction path. On the basis of these criteria
two different classifications are performed. The first one is based on the first two criteria
(HAND and slope), whereas the second one includes all three criteria. Artificial Neural
Networks (ANNs) are employed as the primary classification method. Since this is a
supervised classification method, it required that a subset of points in each test basin be
independently classified with the aim to construct data sets for training, testing and
validation. Orthophotos are used to assist this manual classification process. These constitute
a by-product of the DEM construction process through using photogrammetric
methods. They offer the advantage of lower cost and processing time with respect
to the collection of field data. The value of this kind of information was assessed
through using unsupervised classification via the well-known Fuzzy c-means (FCM)
method. Five classes of landscape are considered: riparian areas, plain areas, low slope
areas, high slope areas, and plateaus. Two drainage basins are used to illustrate
the proposed methodology. The first basin is the Erasinos river basin in Eastern
Attica, Greece, while the second basin is that of the Sarantapotamos river in Western
Attica. The first basin is predominately semi-mountainous, while, in the second
one, differences in elevation are more pronounced. Landscapes of the two basins
are typical in the Mediterranean region. Classification results are discussed and
compared to findings from other similar studies. Further validation is provided through
using data from a limited field data collection campaign in the Erasinos basin.. |
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