The impact of wildfires on society is increasing. Annually burned area, fire season length and fire severity have increased during the last decade in several regions of the world, and a number of tragic events have occurred recently in fire-prone areas. Whereas forest fires are natural phenomena, emergency management must be improved in order to minimise human and economic losses as well as undesired effects to ecosystems not resilient enough to fire. However, wildland fire behaviour is not completely understood. Fire rate of spread depends on terrain, weather and vegetation, but the exact relationship between all involved variables is unknown. Remote sensing can help to solve this issue because it has a great potential to measure real-scale fire behaviour with a high spatio-temporal resolution. In this paper, we propose the use of a Geographic Information System (GIS) to combine wildfire remote sensing data with spatial information about vegetation, weather and terrain. This integrated framework facilitates the systematic analysis of multisource data and the study of observed relationships between variables. We describe which operations may be applied to remote sensing and geospatial data in order to display the observed fire evolution and extract relevant statistical relationships. Among others, fire spread is displayed over a topographic map; burned area and fire perimeter evolution are measured; spatially-explicit rates of spread (ROS) are computed; surface ROS is derived from horizontal ROS using a Digital Elevation Model (DEM); and relationships between ROS, intensity, slope and vegetation type are studied.
Airborne thermal infrared (TIR) imaging systems are being increasingly used for wild fire tactical monitoring since they show important advantages over spaceborne platforms and visible sensors while becoming much more affordable and much lighter than multispectral cameras. However, the analysis of aerial TIR images entails a number of difficulties which have thus far prevented monitoring tasks from being totally automated. One of these issues that needs to be addressed is the appearance of flame projections during the geo-correction of off-nadir images. Filtering these flames is essential in order to accurately estimate the geographical location of the fuel burning interface. Therefore, we present a methodology which allows the automatic localisation of the active fire contour free of flame projections. The actively burning area is detected in TIR georeferenced images through a combination of intensity thresholding techniques, morphological processing and active contours. Subsequently, flame projections are filtered out by the temporal frequency analysis of the appropriate contour descriptors. The proposed algorithm was tested on footages acquired during three large-scale field experimental burns. Results suggest this methodology may be suitable to automatise the acquisition of quantitative data about the fire evolution. As future work, a revision of the low-pass filter implemented for the temporal analysis (currently a median filter) was recommended. The availability of up-to-date information about the fire state would improve situational awareness during an emergency response and may be used to calibrate data-driven simulators capable of emitting short-term accurate forecasts of the subsequent fire evolution.