Tuesday, August 30, 2011

Lab 4, Station Fire Hazard- Spatial Analysis

               Using GIS can be very helpful for mapping out fire hazards. You can easily analyze where a fire is most likely to occur by creating a hazard map with certain characteristics, elevation/slope and land cover/vegetation. Using GIS can also be a less dangerous way to research the flammability of certain vegetation in a given area. By analyzing the maps, you can see that the Station Fire in 2009 in Los Angeles burned where the vegetation had moderate chances of catching fire rather than higher risk areas. To make the maps, I first gathered all the needed data, such as the perimeter of the Station Fire, the DEM, and land cover, and loaded it to ArcMap. I then created a hillshade for the Los Angeles County and added the slope characteristic to show elevation and reclassified the land cover to show where the fire had burned within the perimeter.
              For this lab, I rather enjoyed making the maps because I worked with my classmates and we helped each other out throughout the whole process. By working together, it made the lab more fun to do. We all had struggles and definitely needed each other’s help and of course, Jida’s guidance to get us through ArcGIS. First, gathering all the data was challenging because we weren’t sure which GIS data we should use from the FRAP database. We downloaded many different files for LA County including Surface Fuels and Fuel Rank, when finally, we concluded that the Multi-source land cover data would be the best to use for our land cover map. Another challenge we faced was reclassifying the land cover. It took a while to figure out how we would rank each vegetation type and actually inputting the data into the reclassify tool took a couple of tries before we got it right. Also, when trying to combine the two maps, the slope map and the land cover map, using the raster calculator, we encountered a small problem. When we would try to input the two layers into the calculator, both weren’t listed. With a little manipulation (and with Jida’s help), we figured out that the layers needed to be activated in order to be put into the calculator. Once the problem was solved, I realized that minor details, no matter how small they are, always need attention. Something as small as not activating a layer can easily frustrate you when trying to complete your map. I definitely learned from that minor mistake and will always remember to make sure every layer is activated. Lastly, choosing a proper color ramp to clearly indicate the presented features was fun, but also a challenge. Overall, I enjoyed working together with my classmates to make these maps.


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