Automatic mapping of surfaces affected by forest fires in Spain using AVHRR NDVI composite image data
✍ Scribed by Alberto Fernández; Pilar Illera; Jose Luis Casanova
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 814 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0034-4257
No coin nor oath required. For personal study only.
✦ Synopsis
In this work, we describe the statistical techniques used to analyze images from the National Oceanic and Atmospheric Administration's' advanced ver~j high resolution radiometer for the calculation and mapping of surfaces affected by large fi)restfires in Spain in 1993 and1994. Maximum value normalized difference vegetation index (NDVI) composites (MVCs) were generated for every ten-day period over the two yeacs" of the study. Two techniques, one regression analysis and the other differencing, were applied to the NDVI-MVCs' both before and after each fire event to determine detection thresholds of change and to delineate and objectively evaluate the burned surfaces. The comparison between the single-fires burned areas predicted by the techniques and that provided by the Spanish Forestr~j Service (ground based) showed that the regression algorithm was more reliable, giving rise to virtually no bias (-0.9%) and a root mean square error (RMS) of 20.3%, both calculated as a percentage of the mean burned area of the whole sample. The technique of differencing provided worse results with a 3.2% bias and a 23.5% RMS error. Likewise, a comparison between the perimeters of the large fires supplied by official data (GPS-based) and those obtained by the regression method cot!fimned the validity of the technique not only fl)r calculating fire size, but als'o fi)r mapping of large forest fires.