WEEK 7: Fire Hazard Mapping

My spatial analysis of the Station Fire was constructed using a variety of data sources and through following the technique demonstrated in the fire model tutorial. My data was acquired through free data providers, where I was able to access a DEM through the USGS’ Seamless website (http://seamless.usgs.gov/website/seamless/viewe r/htm), a vegetation shapefile through the California Department of Forestry and Fire Protection (http://frap.cdf.ca.gov/data/frapgisdata/download.asp?spatialdist=2&rec=hardwoods), and a fire perimeter polygon through the Rocky Mountain Geographic Science Center (http://rmgsc.cr.usgs.gov/outgoing/GeoMAC/2009_fire_data/California/Station/).

I followed techniques as taught by the fire hazard mapping tutorial, correcting my data to correlate in resolution and in geographic projection. I then created a hillshade from my DEM layer, from which I was able to create a slope layer through the spatial analyst tool, allowing an assessment of fire hazard based on steepness. Next, I converted my vegetation polygon from a vector to raster image, allowing reclassification of data. I also extracted the vegetation type from the vegetation polygon, allowing a classification of land cover. The land cover classification provided a clear image of fire boundaries and fuels in relation to vegetation. Finally, using the raster calculator, I combined the vegetation (fuel) hazard with the steepness of slope fire hazards, providing a robust assessment of fire hazards in the Station Fire.

While building the necessary map layers, problems arose, involving data collection and mismatched data projections. The most frustrating obstacle posed during the spatial analysis was by far the task of collecting data. While the DEM shapefile was found quickly through USGS Seamless.), a concise perimeter and an adequate vegetation layer were found only after tedious and time consuming internet-searching. For the vegetation layer, contrasting projections, or incorrect coordinate boundaries were common obstacles, as well as the fundamental problem of incomplete data. For example, some layers only incorporated hardwoods, were obsolete, or were poorly classified. Another problem pertained to the Station Fire perimeter, involving contrasting coordinate boundaries, mismatched projections, or a polygon of only one stage of the fire (opposed to a summary of the fire’s progression).