Lab 7: LA Station Fires

Above I have two maps, one is a reference map of Los Angeles county, with a hill shade of the region, along with the major highway and road system mapped out in white, with the area of the 2009 station fires outlined (each outline represents a day of the fire, starting August 29th going through September 2nd.) The second map is more zoomed in towards the fires, with the slope of the area shaded. The outline colors of the fire were changed because the orignial colors were difficult to tell apart from the slope colors, with red being the highest slope and green being the flattest.

The Station fire which we are focusing on, took place in Northern LA county, and burned around 160,000 acres and began in late August and continued through October (due to some rainfall) and ended up be coming the 10th largest in California history. As the fire grew, it came to threaten nearby Pasadena, La Crescenta, Glendale, La Canada Flintredge, and Altadena to just name a few. Mandatory evacuations were initially imposed, but by the end of the first week of September, the residents were allowed to return back home.(Wikipedia) To many, the fire seemed surreal, with photos capturing images that looked not of this world, some even compared it to the hellish realm of "Mordor" in the Lord of the Rings for it's unending flames that continued into the night. (boingboing.net) Though the origins of the fire were intially unknown, it was discovered that arson may have been the cause. (Wikipedia, Inciweb).

Slope is one of several factors (among altitude, solar exposition, and overall surroundings) which determines the type of climate, vegetation cover, and wind pattern. According to Viegas' article slope is "the main topography element affecting directly the fire propagation." The rate of the fire climbing increases the larger the slope (2910). And this theory is tested to be true; if we examine my map more closely we can see that indeed the fire grows in the direction of the slope, and from the articles I have read and what I heard on the news, it grew at an astounding pace.

So if we examine my second map more closely, we can see that the first ring of fire begins on an area of relatively high slope (it's not green- its red/orange/yellow), and as the fire increases, it increases in the direction the slope is going (North), and heads in that direction, it does not head south, were the slope is minimal and relatively flat (green), but towards the hills where the slope is going up, and the fire continues to the climb upwards along this slope. I imagine that if the fire were not contained that it would continue to climb upwards, and eventually pan out laterally, to the other few areas of high slope and climb over those foothills too.

And so we can see that slope is one of the major aspects of the propagation of this Los Angeles Station Fire, and that the evidence shows us that indeed the fire followed the slope of the mountains in its course. And though it is not the reason the fire started or the only reason the fire grew so quickly (chapparal also played a great role), slope can definitely help us predict where the fire is going to spread next.



Downloads from:
http://gis.ats.ucla.edu/ (LA county, highways)
http://gis.lacounty.gov/eGIS/?p=1055 (Station fires)


Information From:
"2009 California Wildfires" http://en.wikipedia.org/wiki/2009_California_wildfires. 12/1/2009


"All Station Fire Perimeters". Los Angeles County Enterprise GIS. 9/02/09. http://gis.lacounty.gov/eGIS/?p=1055. 12/1/09.

"Incident Overview. " Incident Information Web. http://inciweb.org/incident/1856/. 12/1/2009.

"2 Firefighters Die as Los Angeles Wildfire Rages" http://www.nytimes.com/2009/08/31/us/31fires.html. 12/1/2009


" Straight Outta Mordor: Notes from the LA Fire"
http://www.boingboing.net/2009/09/01/straight-outta-mordo.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+boingboing%2FiBag+%28Boing+Boing%29. 12/1/2009

Viegas, Domingos Xavier. "Fire Dynamics" Philosophical Transactions: Mathematical, Physical and Engineering Sciences, Vol. 356, No. 1748, The Royal Society(Dec. 15, 1998), pp. 2907-2928

Lab 6: DEMs!

1) For this Lab I chose as my area of interest Lake Tahoe and it's surrounding shores in California/Nevada in the United States, a place where I visit in the winter fairly often. I felt that it would be interesting to see the great disparity between the still surface of a lake (or even if it was represented as flat in an elevation model) and the huge mountain ranges surrounding it. The DEM that I obtained from the USGS site uses the North American GCS from 1983, and the extent of the DEM is (approximately) Top: 39.256 decimal degrees, Left: -120.343 decimal degrees, Right: -119.801 decimal degrees, and Bottom: 38.880 decimal degrees.

2) Shaded Relief Model

3) Slope Map

4) Aspect Map

5) 3D Image

Lab 5 Projections!

Undoubtedly map projections are extremely important in not only the world of geography, but also any time maps are used. Representing the spherical earth onto a 2D plane is no simple task, and it is essential to be precise and exact in one's conversions in measurements so as to best represent the world. By allowing us to represent the Earth's surface in 2D, projections allow us to explore the world by simply looking at a map or a computer screen, both mediums which (obviously) require the world to be "flat" since these are much more portable and convenient than carrying around a globe.

What I never knew before this class was that there were so many different types of map projections with a variety of representations, some of which I find nearly unreadable (such as the equal area Bonne map I have created above). One goes about choosing a projection based upon what one wishes to accomplish: navigation, radio and seismic mapping are just a few of the things one could base their decision on. Obviously one would want to have a map best suited to one's particular needs.

For example, in conformal map projections (such as the Mercator and Gall-Stereographic I created) preserves the angles of the map, and has rhumb lines (a straight line on the projection) which show true direction, and would help a navigator see that he could reach a certain point if he keeps a constant bearing. Equidistant projections maintain the true distances from the center of the projection (such as in Plate Caree and Sinusoidal) which is great if one is interested in measuring things in relation to the center. In equal area projections, (Bonne and Molleweide), the areas of the Earth's surface are maintained at a smaller scale and not distorted.

But just are there are advantages to having these different projections to represent the maps differently, there are also disadvantages. What if one has all these options but is no expert in GIS? How does one choose which projection? As we can see, distance is most definitely not constant across all maps -- the distance measured between Washington DC and Kabul is different in every single projection, with great differences between them (even of the same projection!). So really without sure knowledge, one leaves it up to some ambiguous authority (Google maps, map quest, the USGS etc) to determine which projection you are to see. Also, without knowledge of which map is appropriate for which usage, one may not be able to determine the precise and correct measurement they are seeking.

And so, though there is some uncertainty involved and danger in choosing one projection over another without knowing potential distortions, having projections is of great use to us where GIS, maps, and GPS are all presented in 2D, and we can't all walk around with globes.

Lab 4

This week I had my first ever experience with the professional mapping program Arc Map. Not only was I overwhelmed and excited at the amount of buttons and things one could create but also (as a Computer Science major) amazed and in awe in how much work and effort must have gone into creating this program. Initially it was really cool to be doing all this stuff, but I must admit as I was stepping through the tutorial I was continual frustrated as I seemed to be having more problems linking things than actually using the program!

My experience was mainly a positive one since I'm fairly computer savvy and the tutorial was pretty clear. However my biggest problem occured in Exercise 3, when we are supposed to "Add Field" to the Attribute table of Tracts. For some reason I kept getting this message that I did not have permission to access something or other and so I couldn't create that data frame. Eventually I got it working after much frustration and moving around of files, but everything else was straightforward with the instructions, but the thought of having to actually make up these maps on my own is rather daunting.

ArcMap is a great tool to be able to pull data together and figure out the overlap and put everything in one visual form. You can see clearly what falls within the noise contour in our example (assuming the data is correct) and though time consuming, is probably much faster than back in the day when everyone had to draw the maps by hand and allows for easy overlapping and organization of data for each component.

However, like any other craft, ArcMap takes time to master and many hours logged at the computer in order for one to be as efficient and clear as possible, considering there are so many buttons, tables, etc etc that are at one's disposal. So though a great tool, it is not an easy one to learn. Also, as easy as it is to present data, it must be equally easy to misrepresent data (like any map) and therefore confuse the audience with your message and not necessarily the facts. Also, it was so easy to just accidentally move something too far or too close, so I imagine one has to be very careful when using the program on a regular basis.