Comparative analysis of the number and intervals of forest fire risk classes

Abstract

The issue of forest fires involves prioritizing areas of attention, based on criteria such as risk, in order to locate and size them on specific thematic maps. Their classification includes: a) selecting the number of risk classes, and b) a process to establish class intervals. However, this varies depending on the appreciation of who specifies such classification. In order to prevent this variation, a comparative analysis is made between two class numbers (3 and 5) and the following alternative categories: Equal Intervals, Quantiles, Natural Breaks, and Geometric intervals. 1 000 validation sites (VS) were located at random on a forest fire risk map of the state of Jalisco (Mexico) in order to determine the number of classes and the method for establishing the intervals. An area of 100 km² was delimited around these sites, where the number of forest fires during the 2005-2014 period was determined. Thus, the risk class corresponding to each of these VS was associated with the number of fires that were located in the 100 km² area. Based on this, the variability (standard deviation) between the classes generated by each of the four methods for determining their intervals was compared. The results suggest that the Equal Interval method is the most suitable for defining the intervals of the fire risk class. As for the number of classes, there is a clear differentiation between the classes when five of these are utilized.