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

BURNED AREAS MAPPING BY MULTISPECTRAL IMAGERY:
A CASE STUDY IN SICILY, SUMMER 2007
P. Conte & G. Bitelli
DISTART - University of Bologna, Bologna, Italy
paolo.conte2@unibo.it; gabriele.bitelli@unibo.it
Abstract: This work reports some experiments in classifying and mapping
the areas which were affected by wildfires in centre-eastern Sicily in June
2007. The study exploited moderate resolution images acquired by ASTER
sensor (Advanced Spaceborne Thermal Emission and Reflection Radiometer)
and compared four types of classification, all of which based on spectral
indices specially developed for this kind of application: BAI (Burned Area
Index), NBR (Normalized Burned Ratio) and MIRBI (Mid-Infrared Bispectral
Index). After assessing each index by means of direct interpretation and
set-up of appropriate threshold values, the method was optimized by their
multiple thresholding. This approach was used for both single images and
multi-temporal series. For each index some confusion errors with different
kinds of surface (e.g. farmed areas, urban areas, water bodies) were reported.
The simultaneous use of the indices made the classification more accurate
with fewer commission errors.
1 - Introduction
Every year Italy is affected by countless forest fires which have a considerable
impact for number of human casualties and extent of economic, social
and environmental damage; in spite of a greater financial and technological
commitment to face such events (e.g. the duty for local government
bodies to draw up and yearly update a cadastre of forest fires), the number
and extent of burned areas have increased from 2006 to 2007. In fact two
recent reports (Indagini Ecosistema Incendi, Legambiente, 2006 and 2007)
show a change in the trend of recent past: in 2006 there had been 5,643
events of wildfires for a total burned area of about 40,000 ha, with a little
improvement in comparison with previous years. Instead, 2007 was a critical
year with 10,614 events (top value since 1997) for a total burned area
of 225,000 ha (top value since 1981), with 23 dead and 26 wounded apart
from heavy economic and environmental damages. The South of Italy is
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