Lab 8

          In 2009, the city of Los Angeles suffered its most destructive fire in history known as the Station Fire named for its origin nearing the Angeles Crest Fire Station in the Angeles National Forest (Mittal 11). Started by arson on August 26th, the Station Fire was not fully contained until October 16 (Mital 1). During its rampage, 160,577 acres of land was burned, 89 homes were destroyed, and two firefighters' lives were lost (Mittal 1). Costing about $95 million to suppress, the Station Fire was also the most expensive fire in the history of United States (Mittal 1). The reference map below illustrates the extent and growth pattern of the fire as well as land use of the areas around the fire.

          From the above reference map it is apparent that the southern parameter of the fire reached high density residential areas, thus resulting in the destruction of civilian houses, closing of schools, and mandatory evacuation from cities such as La Canada Flintridge, Altadena, Glendale, and La Crescenta (O'Connor). Additionally, major roads such as California State Route 2 were cut off due to the extent of fire. From the map, one might notice that the growth of the fire, especially when it first started, seems to progress mainly in a northward direction. This can be explained by the tendency of fire burning uphill faster than downhill. Since flames and heated air always move upward, areas above a fire are not only more prone to be lit on fire but also are heated by hot air from below, making them drier and more suitable for fire. As the Angeles National Forest has a steep slope facing south, it would be natural for the fire to rapidly grow northward.

          With 25% of its land burned, the city of Los Angeles faced yet another threat even after the fire was extinguished. Without plants to buffer the rainfall and roots to stabilize and hold together the soil, the bare land after a wildfire is extremely vulnerable to erosion. Also, due to the effect of hydrophobicity, a process through which the chemicals released from the combustion of plants condense to form a waxy coating on the ground, soil becomes repellent to water and rate of water runoff is thus increased (Moench & Fusaro). Erosion not only posits a problem for agriculture due to soil loss, but also causes great danger to lives and properties of people in the form of landslides. Since the Station Fire took place on a landscape with steep slope, the possibility of landslides was very high. To make things worse, the threat was imminent because the fire ended right before winter season. To gauge the potential and threat of erosion and landslides after the fire, I created a thematic map showing the distribution of different levels of post-fire erosion potential across the county.

          The post-fire erosion potential level is calculated based on the Revised Universal Soil Loss Equation. The equation follows roughly as: A= R * K * L * S * C * P, where A is soil loss in tons per acre per year; R is the rainfall erositivity factor measured for each area; K stands for soil erodibility which is dependent on the composition of soil at a given area; L and S are the topographic length-slope factors that measure steepness; C is the factor of soil coverage; and P takes erosion preventive practices into account (Jones and Kowalski and Shaw). From the map, it is apparent that the area where the Station Fire took place has very high erosion potential as predicted. Moreover, the mountain range with the highest post-fire erosion potential seems to be directly adjacent to residential areas, causing the situation to be even more threatening. 

          As countermeasures for landslides, the Los Angeles county government deployed a number of methods and treatments. Damaged and hazardous trees were fell to ensure safety and slow water runoff (Station Fire Burned-Area Report 13). Sandbags and k-rails were used to block overland flow and protect assets. Additionally, a design combining k-rail and chainlink fencing called rock fall catch fences were used to further minimize damage to people or properties (Station Fire Burned-Area Report 13). Woodstraw mulches were applied to increase soil stability (Station Fire Burned-Area Report 13). Additionally, contour log terraces could be placed to stabilize soil and stop water runoff (Moench and Fusaro). Since an ecosystem is extremely vulnerable to exotic or invasive plants immediately after a stand replacing fire, the prevention of weed growth is also important for both erosion prevention and ecosystem protection. Since weeds do not have strong roots capable of stabilizing the soil, their growth is not only useless but also harmful to the process of restoration as they hinder the regrowth of native plants. 

------------------------------------------------------------------------------------------------------------

References

Jones, David S., David G. Kowalski, and Robert B. Shaw. "Calculating Revised Universal Soil Loss Equation (RUSLE) Estimates on Department of Defense Lands: A Review of RUSLE Factors and U.S. Army Land Condition-Trend Analysis (LCTA) Data Gaps." Http://www.cemml.colostate.edu. Center for Ecological Management of Military Lands, n.d. Web. 22 Mar. 2013. <http://www.cemml.colostate.edu/assets/pdf/tps-96-8.pdf>.

Moench, R., and J. Fusaro. "Soil Erosion Control after Wildfire." Soil Erosion Control after Wildfire. Colorado State University, 3 Aug. 2012. Web. 22 Mar. 2013. <http://www.ext.colostate.edu/pubs/natres/06308.html>.

O'Connor, Robert. "CFN - CALIFORNIA FIRE NEWS - CAL FIRE NEWS : Station Fire Evacuations: Mandatory Evacuation Orders." Web log post. Station Fire Evacuations: Mandatory Evacuation Orders. CALIFORNIA FIRE NEWS, 30 Aug. 2009. Web. 22 Mar. 2013. <http://calfire.blogspot.com/2009/08/station-fire-evacuations-mandatory.html>.

United States. Department of Agriculture. Station Fire Burned-Area Report. USDA Forest Service, 23 Sept. 2009. Web. 19 Mar. 2013. <http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5245056.pdf>.

United States. Government Accountability Office. STATION FIRE Forest Service’s Response Offers Potential Lessons for Future Wildland Fire Management. By Anu K. Mittal. United States Government Accountability Office, 16 Dec. 2011. Web. 18 Mar. 2013. <http://www.gao.gov/assets/590/587075.pdf>.

Lab 7

This map illustrates the distribution of African American population as percentage out of the entire population in each county. In the map, African American population is mostly concentrated in the southwest coastal region of the continental US, reaching as high as 86% of population for certain counties. This is understandable from a historical perspective, as most African Americans first arrived in the United States as slaves in the colonial region. Since slaves were most needed in the south for cotton production, much African American population remains in the south rather than the north. African American population then remains sparse throughout the rest of the continent, with some concentration at the west coast.

This map shows the distribution of Asian population in the same way as the previous map. Asian population is mostly concentrated at the west coast, with some scattered counties with higher percentage of Asian population in the central area. There are also regions with high Asian population percentage at the northwest of the continent. Certain counties have Asian population percentages that are as low as 0.0085%, while counties with the highest Asian population only have 46% of Asian population. The concentration of Asian population at the west coast can be explained by the history of Asian immigration, as lots of Asian immigrants first arrived in San Francisco as a result of the Gold Rush.

This map shows the distribution of population of races other than white, black, or Asian. Since the population in the United States other than that of white, black, or Asian is mainly made up of Hispanics or Latin Americans, the map therefore reflects the distribution of the population of Hispanics. As one would expect, the population of Hispanics is mainly concentrated at the area directly north of Mexico and areas that were historically part of Mexico, including Texas, New Mexico, and California. There also seems to be areas with high population of races other than white, black, or Asians in Idaho and Washington states. However, whether those races are of Hispanic origins is rather unclear.

------------------------------------------------------------------------------------------------------------

          The utilization of GIS is an excellent method for quick and easy to understand representation of the census data. At a glance, one can easily see the distribution of a certain population. From the maps that I created, population of all races tend to concentrate at coastal areas and the border of the country while northern regions of the continent seem to have less population. Also, historical factors play a major role in determining where a certain race mostly populates. In other words, places where a race first arrived at or immigrated to usually became where the population grew the fastest and thus the source of later emigration.
          The maps that I created also taught me many facts that I would have discovered myself. Coming from an area heavily populated by Asians, my impression of Asian population in the United States is thus biased. As a result, I was a bit surprised to see how little area Asians actually populate in the United States. Moreover, I was even more surprised to see the maximum percentage of Hispanic population being lowered than that of Asian population, as this fact seems to completely contradicts with my experience living in Los Angeles.
          The impression given by the maps, however, may not entirely reflect reality due to certain reasons. Since the color ramp in each map is based on percentage per county, the maps should not be used to compare populations of different counties since each county's total population varies. Also, the maps do not portray an accurate representation of the actual number of population of a race. Due to the difference in each county's total population, an overall higher ratio does not always mean higher total quantity and vice versa. Furthermore, since the maps are based on populations of counties, political factors  may have an huge effect on the ratio of a population of a race. For example, certain ethnic groups may seem like minorities or having low population percentages purely due to the effect of gerrymandering.

Lab 6

3D Model

------------------------------------------------------------------------------------------------------------

        This week's lab is focused on performing spatial analysis in ArcGIS based on a particular form of raster data called the digital elevation model. A particular area is divided into raster sectors, with elevation data assigned to each. The process of creating various representations based on the raster data was enjoyable and intriguing as we are allowed to choose a color ramp to our liking. I was particularly fascinated by ArcScene and its presentation of raster data using 3D graphics. Being able to actually rotate and view the area from all 360 degrees gave me more information about the area than any other 2D maps. The process of creating the other 2D maps was quite simple and painless. The spatial analysis tool from ArcToolbox was extremely helpful and did almost all the necessary work for me, including dividing data into subgroups and assigning color ramps based on it. It was, however, a bit inconvenient that I could not find the units used for the data in each raster layer easily. As a result, the legends may appear confusing to readers who don't know the units beforehand. Also, there seemed to be some glitch within ArcScene, such that a corner of the 3D landscape turned blank after I left the program idle for some time. I tried rotating and zooming but the problem persisted. Fortunately I exported the image before this glitch occurred. 

Lab 5

        
          In this week's lab we explore a variety of global map projections along with their strengths and weaknesses. Since the earth is a three-dimensional object, it's not possible to project its surface onto a continuous two-dimensional surface without distortions. As a result, no map is truly equidistant in such a way that all distances between any two points on the map are of the same scale. Given that there no perfect way to project the earth's surface, many different projection methods were invented to preserve certain geometric elements at the cost of distorting the others. 

          One element of such is the shapes earth's continents. In order to preserve shapes, angles must be locally preserved. Maps that preserve angles are called conformal. In a conformal map, longitudes and latitudes must intersect at right angles, and from any given point scale should be the same in all direction. This does not necessarily mean that conformal maps have one consistent scale throughout the entire map. Most conformal maps in fact have different scales in different zones. The most popular and widely used conformal projection is the Mercator projection, in which loxodromes on the globe (line that cross meridians at a constant angle) are simply straight lines on a Mercator map. This feature proved to be very useful for nautical navigation. However, conformal projections such as the Mercator have many limitations. For example, a straight line between two points on a Mercator map is often not the shortest route (geodesic line) between those points on earth's surface. Also, area distortion worsens when moving away from the equator. As a result, Mercator maps suffers area area distortion so severe in the polar regions that most Mercator maps are clipped between 85 degree North and South.

          Of all the geographic elements, area is perhaps the most important and useful one for the application of maps. Accurate presentation of area on maps are crucial for the analysis and comparison of data regarding geographical distribution. As a result, many equal-area projections were invented for this purpose. On an equal-area map, the ratio of any two areas is always the same as the actual ratio on the globe. The preservation of area, however, comes with distortion of shape as a cost. In the maps of cylindrical equal-area projection and sinusoidal projection, shapes of continents toward polar regions seem extremely compressed in order to maintain their corresponding small surface area. Besides area, distance between two points is another important geometric factor that is preserved by many map projections.  However, as mentioned earlier, no map is truly equidistant; instead, most equidistant maps only have a limited number of lines that have the same consistent scale throughout their lengths. For example, in the Azimuthal equidistant projection only distances of straight lines that pass through the center of the map are preserved. As for the cylindrical equidistant projection, only the meridians and equator are of consistent scale. Horizontal scales rapidly increases as one moves vertically away from the equator. 

          Choosing the right map projection is all about knowing which geographic element is important for the purpose of the map and compromising between them. For example, aesthetically, conformal maps are favored for their accurate portrayal of shapes, while equal-area maps are extremely important for GIS because of their ability to accurately present the distribution of a certain attribute per unit area. However, one would be mistaken to think that every map favors just one geographic element. In fact, there are plenty of projections that attempt to compromise between different map properties by not strictly preserving any single one of them. For example, the Robinson projection, though neither conformal nor equal-area, compensate by bending meridians slightly to reduce distortion toward the poles but not enough to get rid of it completely like the sinusoidal projection. 

Lab 4

 

                

               In lab 5 from week 4 we finally began the instruction and operation of a professional GIS system named ArcGIS. The assignment of lab 5 is to utilize ArcMap from ArcGIS to create maps which outlines an airport expansion along with data on lands that will be affected by the proposed expansion. Given this my first experience with a GIS system, I was both excited and a bit intimated by the seemingly complicated interface. Fortunately, thanks to the extremely detailed and step-by-step tutorial PDF I was able to progress smoothly through the assignment with little difficulty until I ran into that infamous bug.
                Like many others from the lab, I encountered a problem such that the population field from the tracts layer would lose all its data once I add an additional field for population density. The problem remains even after I attempted the steps aimed to resolve this issue suggested by the TA. Finally, in the following lab session I found that I am not supposed to delete the newly created population density field when I attempt rejoining even if it’s filled with null data.  After overcoming this troublesome bug I managed to proceed and finish the assignment without much difficulty. The only other problem that I encountered was toward the end when the instruction manual requires us to modify the elements of the legend for the schools and noise contour map without demonstrating how to do so. Fortunately it didn't long for me to find the right options in the legend properties window.
               Though my overall experience with ArcGIS was pleasant, there were definitely some inconveniences in the process. For example, many actions or events in ArcMap cannot be undone through the edit menu. This is especially frustrating for me because most programs that I've used trace every action such that mistakes can always be fixed with a simple ctrl+z. Moreover, the display area does not seem to be synchronized with the table of contents. For instance, ArcMap doesn't automatically reflect my selection in the display area unto the table of contents. It would be more convenient if a layer in the table of contents is automatically selected whenever I click on the corresponding layer in the display area. Another slight inconvenience is that browsing seems a bit unintuitive in ArcCatalog, especially when I try to navigate to an arbitrary folder that’s not under the root directory or existing database locations.
                GIS systems such as ArcGIS are an essential tool for professionals such as geographers or engineers. In ArcGIS, data are organized into layers so that different kinds of data can be easily edited without affecting others. Layers also enable maps to display different level of information on top of each other at the same time. ArcGIS also allows users to embed lots of useful elements, such as texts, legends, or scale bars to make their maps more informative. However, the sheer amount of functionalities within ArcGIS makes the program seems rather complicated. Without a user-friendly interface or extensive tutorials, ArcGIS may appear daunting to beginners or non-professionals.  Also, license for a professional GIS application like ArcGIS is rather expensive. Most people would be limited to neogeographic tools because of the extensive amount of money and time needed for professional GIS tools. 

Lab 3

      The map below is a short tour I created for Six Flags Magic Mountain. I've only been to Six Flags Magic Mountain once and was not able to visit all the rides. This tour highlights the ones that I want to visit if I ever get the chance to go again.



View Six Flags Magic Mountain in a larger map
     
------------------------------------------------------------------------------------------------------------

 In the age of neogeography, maps development is no longer a privilege limited to professionals. Anyone given internet access is able to create and share geographic information with others. Maps may contain not only empirical data such as elevation or geographic coordinates, but now also personal information such as tagged photos or reviews for tourist attractions. As a result, maps can be more informative and easier to understand as people may find certain information easier to relate to. For instance, two maps of the same location, while one has photos tagged by celebrities, would have very different meanings to people reading them.
        However, the freedom of neogeography also comes with a cost. Just like the internet itself, greater accessibility and publicity usually results in overall decrease in quality. As more and more people from the general public are able to publish maps, the average quality and reliability of all maps are expected to fall, as non-professionals are prone to provide inaccurate or biased data.

Lab 2

1.  Beverly Hills Quadrangle

2.  Northwest: Canoga Park
     North: Van Nuys
     Northeast: Burbank
     West: Topanga
     East: Hollywood
     South: Venice
     Southeast: Inglewood

3.  Topography first compiled in 1966.

4.  North American Datum 1927

5.  1:24000

6.
    a) 5cm*24000 = 120000cm = 1200m
    b) 5*24000 = 120000
        120000 in = 10000 ft = 1.89394 miles
    c) one mile = 5280 ft = 63360 in
         63360 in/24000 = 2.64 inches
    d) 3 km = 3000 m = 300000 cm
        300000cm/24000 = 12.5 cm

7. 20 feet

8.
    a) 34° 4' 28.3188" N, 118° 26' 21.1956" W ; (34.074533,-118.439221)
    b) 34° 0' 27.2232" N, 118° 29' 59.0526" W ; (34.007562,-118.499737)
    c) 34° 7' 12.4284" N, 118° 24' 36.9282" W ; (34.120119,-118.410258)

9.
   a) 177m or 580.709 ft
   b) 42.672m or 140 ft
   c) 194m or 636.483 ft

10. zone 11

11. Northing : 3763000, Easting: 362000

12. 1000000 square meters

13.

14. 14 degrees east

15. The steam flows south because the elevation decreases that way.

16.