Tuesday, November 23, 2010

Lab 7: Mapping the Station Fire in ArcGIS



The Station Fire in Los Angeles County started on August 26, 2009 and was fully contained on October 16, 2009 at at 7:00 p.m. The fire burned approximately 160,577 acres of land and destroyed 209 structures, including 89 homes. It was the largest fire in Los Angeles County and the tenth largest fire in California since 1933. The fire started in the Angeles National Forest and severely affected the cities around it.
The first map shows the perimeters of the Station Fire from August 29, 2009 to September 2, 2009 at many different times. The second map only shows the perimeters of the fire on August 29, 2009 at 2:48 a.m. and September 2, 2009 at 7:02 a.m. It can be inferred from the second map that fire tends to go up the slope by looking at the elevation changes. The fire went from the red perimeter upwards toward the purple mountain and its final position is depicted by the orange perimeter.
The Station Fire affected many of its surrounding cities which included La Cañada Flintridge, Glendale, Acton, La Crescenta, Littlerock, Altadena, Sunland, and Tujunga (Wikipedia). None of these cities are actually within the perimeters of the fire according to my second map, which shows how destructive the fire was as it could affect its surrounding cities as well. Many people in these cities were forced to evacuate and there were a lot of people in other cities that were affected by the smoke and the ashes in the air.
The theme of my map is the effects of the Station Fire on potential cities. Condor Peak is the only place that is fully within the perimeters of the fire, so I hypothesize that it would receive the most damage by the fire. The cities in the San Gabriel Valley below the fire would experience aftermath of the fire such as bad air quality caused by the smoke and ashes.
This week's lab is really interesting because I remember seeing the fire in the mountains from my home back in Arcadia, but I had never really thought about how the fire moved or how it affected its surroundings back then. I think it is incredible that ArcGIS can be used to analyze patterns and provide explanations for situations that happen in real life.
Works Cited
"2009 California wildfires." Wikipedia, the free encyclopedia. 2009. Web. 23 Nov. 2010.
Archibold, Randal C. "After a Devastating Fire, an Intense Study of Its Effects." New York Times. 2 Oct. 2009. Web. 23 Nov. 2010. 
"How Did the Station Fire Start." Slate. 3 Sep. 2009. Web. 23 Nov. 2010.
"State of the Climate Wildfires Annual 2009." U.S. Department of Commerce. 8 Jan. 2010. Web. 23 Nov. 2010.
"Station Fire." Incident Information Web. 10 Nov. 2009. Web. 23 Nov. 2010.

Wednesday, November 17, 2010

Lab 6: DEMs in ArcGIS







I chose to do this lab assignment on Grand Canyon because it is a famous attraction located in Arizona. It is a steep canyon carved by the Colorado River and known for its dramatic elevation changes. The geographic coordinate system used is the North American Datum of 1983. The extent information (in decimal degrees) of my original DEM is:
Top: 36.3608333326
Left: -112.540277777
Right: -111.69361111
Bottom: 35.9647222214

Tuesday, November 9, 2010

Lab 5: Projections in ArcGIS

 

Getting Started Questions:
How many degrees does the equator span?
360 decimal degrees
How many degrees do the northern- and southern-most graticule lines span?
180 decimal degrees
What do these two lines in fact represent?
These two lines represent the total distance in decimal degrees around the Earth latitudinally and longitudinally.
Approximately how many miles separate Washington, D.C. and
Afghanistan when crossing the Atlantic?

6,913.151 miles
Mercator Projection: 
Is Alaska really bigger than Brazil?
Yes
What about Greenland?
Yes
How far is Washington, D.C. from Kabul now?
10,110.689 miles 

Map projection is essential in creating maps as it allows a better understanding of the three-dimensional world by representing it on a two-dimensional surface. It also provides a more transportable model as well. Cylinders, cones, and planes are all used to create map projections. Map projections are constructed to preserve one or more of the map regions properties including area, shape, direction, bearing, distance, and scale. Different map projections exist depending on the purpose but no map can perfectly represent the surface of the entire Earth.

Equal area projections such as the Bonne projection and the Sinusoidal projection preserve area. They keep the areas on the Earth and their corresponding areas on the equal area map proportional. In other words, given any two regions A and B on the Earth and their corresponding regions A' and B' on the map, the surface ratios of A to A' and B to B' are the same.

Equidistant projections preserve distance from some standard point or line. These include the equidistant cylindrical projection and the equidistant conic projection. They maintain equal distances from the center of the projection to any other place on the map in all directions, but area is distorted as a result.

In conformal projections such as the Mercator projection and the Gall Stereographic projection, angles are preserved locally. The Mercator projection is the most widely-used conformal projection. It is a cylindrical map projection and is used for nautical purposes because of its ability to represent rhumb lines as straight segments. It is good for preserving the angles and the shapes of small objects, but it distorts the size and shape of large objects as the scale increases from the equator to the poles.

Map projection is the method of taking the surface of a sphere or other shapes and representing it on a plane. Inevitably, distortions occur during the transformation of a 3-D model to a 2-D surface and some information is lost in this process. Despite these perils, map projection is significant in creating maps and its variablility allows the user to choose and construct the best-possible representation of the desired model depending on the situation.

Wednesday, November 3, 2010

Lab 4: Introducing ArcMap

This week's lab was a lot more difficult than last week's lab exercise. While Googlemap was relatively straightforward and easy to understand, GIS was really difficult and confusing for me even with the tutorial.This further reinforces the point that neogeography is for amateurs while GIS is for professionals. Even though it is quite complicated to use, GIS has proven to be an effective and helpful mapping tool.

A problem I encountered while doing the lab was saving the data onto different computers, so when I opened my completed project on another computer some of the data and the graph were no longer present. I ended up having to redo the whole thing several times to finally get it right. Another problem I had was not being able to undo some of the things such as color changes and had to change it back manually.

GIS has great potential in helping users understand the spatial relationship between a place and its attributes through the use of maps. It lets users incorporate graphs and maps together to better understand and solve real-world situations. For example, the map for this lab exercise is used to help people understand the relationship between the airport noise and its surrounding population so that measures can be taken to solve this problem. GIS is extremely helpful in mapping out data, visualizing the relationship between data, and analyzing the data.

Despite its potentials, GIS contains certain pitfalls as well. First of all, GIS is not user-friendly for first-time users. A lot of steps have to be taken to perform a simple operation. The program can be very confusing for amateurs unless they go through the tutorial several times. Another downside of GIS is that it is not easily accessible by the public since the program is quite expensive. Therefore, GIS is mostly utilized by professionals and the government to understand real-life problems and develop ways to solve them.