Lab - Week 8

The Station Fire, the largest and most damaging of the 2009 California wildfires, began in Angeles National Forest, near Highway 2 north of La Canada Flintridge on September 26. The initial attack on the fire was unsuccessful due to two factors. First, rough terrain in the area of the outbreak made transportation of firefighting equipment by ground difficult. Second, dry and thick vegetation covered the surrounding area, creating an extremely volatile environment which posed significant risk to firefighters.

The fire mostly spread north through the vegetation of the Angeles National Forest, becoming the most devastating since the forest was officially named in 1892. By the morning of August 31 the fire was only 5% contained and had burned 85,000 acres, destroying 18 structures. It spread north through the forest, endangering structures in the city of Acton to the north, and to the south, endangering the northern areas of the cities of La Crescenta, La Canada Flintridge, and Altadena. Residents of these areas experienced forced evacuations to nearby high schools.


By September 1 the fire had burned nearly 122,000 acres and destroyed 53 structures, and remained 5% contained. Residents of northern Glendale and Tujunga were now forced to evacuate. Though the fire was 22% contained by September 2 the fire, it had burned 140,000 acres and destroyed 90 structures including 62 residences.

The map above shows that most of the fire's growth occurred between August 29 and September 2. Its rapid growth was attributed to strong winds as well as the volatile, dry nature of the vegetation in the Angeles National Forest. Assisted by increased humidity, firefighters were finally meeting some success in containing the fire, with 50% by September 6, when all forced evacuations had ceased. The fire was not fully contained, however, until October 16, 2009, with the assistance of rain. In total it had burned 160,577 acres and cost nearly $90 million. Restoration and rehabilitation of affected areas in the Angeles National Forest had begun.

One of the most significant effects of the Station Fire is the tremendous environmental damage it inflicted. 73% of the soil burn was classified as moderate to high. Since the Angeles National Forest has considerable tectonic activity, with multiple fault lines, its terrain is dramatic (as shown in the map below), with over half of the slopes in the burn area have a grade of 50% or more. These two factors along with the new lack of vegetation create a significant risk of erosion and sedimentation, which pose a threat to people and property in the Angeles National Forest and in the aforementioned communities. Devastating landslides and debris flow may occur in a storm.



Resources

"InciWeb the Incident Information System: Station Fire." inciweb.org. Web. 18 Nov. 2009. http://inciweb.org/incident/1856/

"Fire and Aviation Management: Station Fire Initial Attack Review." United States Department of Agriculture Forest Service , 13 Nov. 2009. 18 Nov. 2009. http://www.fs.fed.us/news/2009/releases/11/station-report-11-13-2009.pdf

"Burned Area Report - CA-ANF 3622." United States Department of Agriculture Forest Service , 23 Sept. 2009. 18 Nov. 2009. http://www.fs.fed.us/r5/angeles/station/BAER/2500-8%20BAER%20Assessment%20Report_Station%20BAER_Public%20Release_10.16.2009.pdf

"Station Fire Growth Slows, But New Areas At Risk" Neon Tommy, 28 Aug. 2009. 18 Nov. 2009. http://blogs.uscannenberg.org/neontommy/2009/08/in-the-news-california-wildfir.html

Millikin, Mary. "Los Angeles fire growth slows with more humidity." Reuters, 1 Sept. 2009. 18 Nov. 2009. http://www.reuters.com/article/latestCrisis/idUSN01488953

Lab - Week 7

These maps are of a rectangle in Fresno County, California, which spans from about 37.0428° N to 37.4367° N and from -118.9336° W to -118.4806° W, using the North American 1983 geographic coordinate system. The highly mountainous terrain in most of the map is the southern end of California's Sierra Nevada mountain range. At the northeast corner of the map is Owens Valley, one of the deepest in the United States, whose western border is the Sierra Nevada.

Hillshade:

Slope:

Aspect:
3D Rendering:

Lab - Week 6

Mercator (Conformal)
Distance measured between Washington DC and Kabul: 10,115 mi
Gall Stereographic (Conformal)
Distance measured between Washington DC and Kabul: 7,164 mi
Sinusoidal (Equidistant)
Distance measured between Washington DC and Kabul: 8,101 mi

Equidistant Conic (Equidistant)
Distance measured between Washington DC and Kabul: 6,971 mi

Bonne (Equal-area)
Distance measured between Washington DC and Kabul: 6,753 mi
Mollweide (Equal-area)
Distance measured between Washington DC and Kabul: 7,895 mi


Because a spherical object such as the Earth can not be flattened onto a plane, map projections are essential. Without map projections we would be limited to only spherical models of the Earth, which, while still useful, lack the flexibility and portability that 2D maps offer. 2D maps can be printed into books, displayed on computer screens, or hung on walls. 2D maps also can inherently display a greater amount of the Earth's surface simultaneously than globes, and consequently are useful for displaying a large amount of geographical data at once (for example, maps displaying worldwide GDP or quality of life.) Thus there is a desire to create accurate map projections.

However, map projections always include some element of distortion because the Earth is not a developable surface. As a result, a multitude of map projections exist, each designed to preserve a certain aspect of the Earth's geometry. Conformal map projections, such as the Mercator and Gall Stereographic projections above, preserve angles, and thus are useful for calculating bearings in navigation. However, conformal projections fail to preserve areas or distances, often with enormous size distortions. In the Mercator projection, for example, the size of areas far from the equator is greatly exaggerated: Greenland appears to be almost as large as the entire continent of Africa, and Antarctica dwarfs every other continent in size.

Equidistant map projections, as their name implies, preserve distances along certain lines or from certain points (since preserving distances from every point to every other point is impossible.) Equidistant map projections are obviously optimal for measuring distances or calculating travel times, but one must be aware of which points or lines conserve actually distance. Measuring the distance from Washington DC to Kabul, Afghanistan using the Sinusoidal projection gave a figure more than 1,000 miles greater than with the Equidistant Conic projection; clearly distance was not preserved along this path.

Equal-area map projections, such as the Bonne or Mollweide projections above, preserve areas. Area distortion is one of the most immediately obvious forms of distortion, and thus equal-area projections are often more visually pleasing than other types of map projections. These projections are useful in thematic maps, maps which associate certain attributes with geographic areas - such as maps of world religions or chloropleth maps like population density. Maintaining area is also useful in statistical analysis of the globe: observing geographic distributions of various phenomena.

Lab - Weeks 4/5

(Click to enlarge)(Extent map for above)

The main advantage of GIS is consolidation of geographic data. When multiple layers of various types of data are combined, geographic patterns begin to emerge. Presenting this data using clear maps makes it easy to read and makes geographic trends immediately obvious. If data were simply displayed in graphs or tables of numbers, it would be much more obscure and citing it to make any arguments would require a good deal of explanation.

GIS software also standardizes geographic data presentation. Maps generated using the same software will tend to look more similar than maps created independently, without the assistance of proprietary software. This further increases readability for people familiar with the world of GIS.

GIS, however, is not without a few pitfalls. GIS software like ArcGIS is tremendously powerful and thus has quite a steep learning curve. Creating effective maps and using such software to its fullest potential requires sufficient training, and may not be intuitive to those trained in traditional methods. GIS software is also very expensive; combined with the learning curve, it may be off-putting to neogeographers who might otherwise be interested.

Effective use of GIS requires a tremendous amount of data, which would be time-consuming to collect. Furthermore, professional GIS-created maps are expected to have a high level of accuracy, so extra caution must be taking in ensuring data is accurate and properly measured.