7th Workshop on Forest Fire Management - EARSeL, European ...

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IV - BURNED LAND MAPPING, FIRE SEVERITY DETERMINATION, AND VEGETATION RECOVERY ASSESSMENT
2 - Materials and methods
2.1 - Study area and satellite data
In the summer of 2007, the year with most destructive fires in recent history
of Greece, a large fire occurred in Parnitha, Greece. This was the study
area for discussing the spectral properties of burnt surfaces at sub-pixel
level using multi-source satellite data. For this purpose, a dataset consisting
by an IKONOS, ASTER, LANDSAT and MODIS imagery was established
after the fire and constituted the basic source of information. The spatial
resolution ranges from 1 to 1000 meters, while the spectral resolution of
the sensors covers the visible, near and mid-infrared, as well as the thermal-infrared
part of the electromagnetic spectrum.
a b
c d
Figure 1 - A dataset consisting by an IKONOS (a), ASTER (b), LANDSAT (c) and MODIS (d)
imagery was established after the fire and constituted the basic source of information.
2.2 - Methods
Classical image processing algorithms were applied to correct geometrically,
radiometrically and atmospherically the available satellite images. The
digital radiometric numbers were converted first to radiance at sensor and
then to surface reflectance to achieve the necessary compatibility for comparing
them. The satellite data were orthorectified using a digital elevation
model created by the 20 meters contour lines extracted from maps of
1:5000.
The very high resolution imagery of IKONOS satellite was served as the basis
for extracting the percent of cover of burnt areas, bare land and vegetation
by applying the maximum likelihood classification algorithm. Furthermore,