Friday, December 9, 2011

Project





There appears to be a problem with my ArcGIS files. This old jpeg file of my reference map is the only thing I can open up now. I will try my best to upload the project from my computer where the original files were made, but it may be after the deadline.

Friday, November 18, 2011

Lab 7




This map show the percentage of Asians by county in the Continental US. It is clear from this that Asian people are more concentrated in the coasts, with the West Coast having greater presence of Asians than the East Coast. I believe this is because of the proximity to the countries of origin, as well as the fact that the coasts are more internationalized with the interior.




This map shows the concentration of Blacks by county in the Continental US. We can see that there is a higher concentration of black population in the southeastern region of the United States. Areas such as Georgia, North and South Carolina, and Alabama show a higher proportion of blacks than the rest of the country.




This map shows the concentration of some other race alone, by county, in the Continental US. This comprises latino, hispanic, among others, so it makes sense that there is a much higher concentration near the US-Mexico border, so states such as California, Texas, New Mexico, will naturally have a higher proportion of "Other races".

The census data is very helpful when applied to a geographical visualization such as this. One can now contrast and compare data while also being aware of spatial locations. To conclude, we can see that the Asian population is more concentrated in the coasts, with the west coast having a higher concentration, the black population is in high concentration in the southeastern region and other races (predominantly hispanic and latino) are more concentrated in the southwestern regions bordering Mexico.

My experience with ArcGIS ended up being very helpful. I can now create maps showing statistical data about various fields. ArcGIS will be very helpful to me in the future, be it in class or in my professional life. It is a tool which allows for the visualization of data in a spatial context, which is extremely useful in economics and the business world alike. I hope I can get to learn more about this complex tool in the future.

Wednesday, November 9, 2011

Lab 6






The area I chose corresponds to the Oahu island in Hawaii, where Honolulu is located. I chose this area because it seemed like an island with some elevation so I thought there would be a good contrast, which there is. The area selected spans from 21.233 N to 21.710 N and from 157.593 W to 158.323 W. The Geographic Coordinate System being used is the North American Datum of 1983.

Monday, November 7, 2011

Lab 5

Bonne Projection - Equal Area Map




Cylindrical Equal Area Projection



Equidistant Cylindrical Projection

Azimuthal Equidistant Projection

Stereographic Conformal Projection

Eckert I Conformal Projection

Distances between Washington and Kabul, using the various map projections:


Projection Distance  between Washington and Kabul (in miles)
Bonne (Equal Area) 6,730.70
Cylindrical Equal Area 10,108.05
Equidistant Cylindrical 5,061.58
Azimuthal Equidistant 8,341.41
Stereographic (Conformal) 9,878.03
Eckert I (Conformal) 7,410.47




 I chose these map projections because they seemed to be extremely interesting. Even among the same type of projection, there is a great difference between the maps: for example, the Bonne projection and the Cylindrical Equal Area projection are both equal area projections, but look extremely different and the distances do not coincide at all. I chose the Equidistant Cylindrical so I could compare it to the Cylindrical Equal Area, since they are both cylindrical projections. On the other hand, the Azimuthal equidistant contrasts with the equidistant cylindrical, but it looks similar to the stereographic conformal. The Eckert I looks interesting just by itself, so I included it to find out how it would measure against the other maps.

We can see that there are great differences between the three types of projections: the equal area projections preserve the areas in the map, but not distances. For example, notice how in the Bonne projection, the longitudinal lines get closer and closer together as they move away from the Prime Meridian; similarly, in the Cylindrical equal area projection, the parallels get closer and closer together as they get farther away from the Equator. This occurs so as to not overstretch the area, maintaining it as close as possible to the real one. The equidistant projections, on the other hand, preserve distances on the maps, but not angles between lines nor areas. This can be seen through the Cylindrical equidistant projection and the Azimuthal equidistant projections: in the former, we see that the distance between the parallels are constant, and this occurs with the lines of longitude as well; in the latter, we see that the intersection of the lines of longitude with the Equator occur at constant intervals, and parallels intersect the Prime Meridian at constant intervals as well, so distances are preserved. Lastly, conformal projections preserve angles between every line on the map, but it does not preserve distances nor areas. In the stereographic projection, we can clearly see that every interception occurs at right angles, and this occurs similarly in the Eckert I projection, except that distortions occur at the Equator.

So how do projections within these types differ from each other? Within the equal area projections, the Bonne and the Cylindrical equal area are significantly different: the Bonne seems to preserve areas from the center outward, with outliers (such as Australasia) being disproportionately large or small; the cylindrical projection appears to maintain areas more accurate for the shapes in the middle band, whereas areas in the utmost top or bottom bands (like Antarctica) are disproportionate in relation to other areas at the center. Aside from this fact, the cylindrical projection yields a rectangular map, precisely because it is cylindrical, so the longitudinal lines are equally spaces. For the equidistant projections, we see that the cylindrical equidistant (which is in fact quite different from the cylindrical equal area), preserves distances alone, since lines are equally spaced throughout the map. However, this leads to distortions in shapes and sizes. With the Azimuthal equidistant projection it is harder to tell whether lines are equidistant, but one can easily see this is true because lines intersect at regular intervals, similarly to the cylindrical equidistant projection. However, there are significant differences between the two: the cylindrical is a rectangular map, and lines are straight; in the azimuthal the map is circular, and the lines (except for the standard lines) are not straight, but rather circular and elliptical. This causes a difference which is similar to that of the Bonne/Cylindrical equal area: distances are preserved closer to the center in the azimuthal, and as one steers away from the center, we begin to see distortions. The stereographic (conformal) projection and the Eckert I projection are very different from each other. Both retain angles, yet the stereographic projection is similar to the azimuthal in the sense that lines are not straight (but neither are they equidistant in this case), and in the Eckert I they are. It also seems the stereographic has a much higher distortion of shapes that do not lie near the center (such as Australasia), and the Eckert I represents this more accurately, as well as the proportions of bodies of land to bodies of water.

Summing up, these projections yield extremely different maps, which we saw through the differences above. Yet, they also yield different distances between the same points. In our case, the discrepancies between distances of Washington - Kabul are seen in the table above. Taking into consideration that the real distance is about 6940 miles, we can see that this puts the Bonne as the most accurate concerning this information, but also tells us something about the other maps: the circular maps overshot on the distance, because distances flow from the center outward; the cylindrical maps are not accurate because the scale between latitudes is similar, and since longitudinal lines are equally spaced, this creates a distortion in distances. The Eckert I is close in calculating the distance, but sacrifices some of the accuracy by accurately portraying shapes and arrangements - which leads me to saying "you win some, you lose some". This tells us that we have to take into mind our purpose when choosing which map projection to opt for: are we looking for accurate distances? or perhaps accurate shapes and arrangements of the bodies of land and water? Are we more concerned with the fact that areas are portrayed accurately? All of these factors should be taken into account when choosing a projection, because most of the time, improving one will sacrifice the other, as it is impossible for all of these factors to remain accurate when projecting from a 3-dimensional spheroid to a flat surface.

Monday, October 31, 2011

Lab 4



NOTE: The original image has the graph in color (tones of red), but I had to reduce the image size because it was too big, so it recolored the graph to grayscale and I do not know how to revert it.


My first impression of ArcGIS was half good and half bad. For starters, it takes a fair amount of time to get used to the program on an intuitive level: one has to go through the tutorial some 3 or 4 times to really get familiarized with the commands presented there - and I'm sure there are many other commands not represented in the tutorial!
What I liked about ArcGIS was the fact that it can be used by non-experts to create high quality maps and tables, an extremely useful feature whose extent is not solely geography. For example, similarly to representing the population density on the map in the tutorial, one can create a map with the density of people living below the poverty line for economics. So, in my opinion this is an extremely versatile program with high quality output.
What I disliked about ArcGIS was, as I have already mentioned, the fact that the commands are not very intuitive, but this is also related to the fact that the program can involve high levels of complexity, so a person has to become familiarized with the program to effectively use it.
There are many commands in ArcGIS of which I am not yet aware of, but which undoubtedly can help one achieve desired goals, not only in terms of geography but also with the study of other subjects, which I am looking forward to learning about.

Wednesday, October 12, 2011

Lab 3




View Lisbon Surfing Trail in a larger map


This is a neogeographical map of a proposed day filled with beaches and surfing in my hometown of Lisbon, Portugal. Neogeography is exactly what is meant by the word: new geography. It allows for user generated geographical content and interaction between users on content relating to geography. It basically allows for people who are not experts in geography to use complex cartography tools and interfaces (e.g. through the use of online maps) and adding their own data to it, for personal use or to share with others for all types of activities (ranging from directions, to references, to sharing memories). This neogeographical map was created using Google Maps, but there are a variety of other websites offering such technology, such as Bing or MapQuest. In this map, I share my recommendation for beach-going and surfing in Lisbon, as well as dining and nightlife, for everyone who is keen on spending a fun-packed day in the coastal capital of Portugal.

Saturday, October 8, 2011

Lab 2


2.       The names of the adjacent quadrangles are: Canoga Park; Van Nuys; Burbank; Topanga; Hollywood; name missing (Pacific Ocean); Venice; Inglewood.
3.       The map was first completed in 1966.
4.       North American Datum 1927 and 1983; National Geodetic Vertical Datum of 1929.
5.       The scale of the map is 1:24000.
6.       A) 5 cm on map = 5 * 24 000 cm = 120 000 cm = 1200 m = 1.200 km
B) 5 in on map = 5 * 24 000 in = 120 000 in; 120 000 / 12 = 10000 ft; 10 000 / 5280 = 1.894 miles
C) 1 mile on ground = 5280 ft; 5280 * 12 = 63 360 in; 63 360 / 24 000 = 2.64 in on map
D) 3 km on ground = 30 000 cm; 30 000 / 24 000 = 1.25 cm on map
7.       The contour interval on the map is 20 feet.
8.       A) 34o 03’ 54’’ N; 118o 26’ 36’’ W  or  34.065009o N; 118.443o W
B) 34o 00’ 31’’ N; 118o 29’ 52’’ W  or  34.008611o N; 118.497o W
C) 34o 07’ 12’’ N; 118o 24’ 39’’ W  or34.120008o N; 118.411o W
9.       A) 581 ft. ; 177 m
B) 141 ft. ; 43 m
C) 636 ft. ; 194 m
10.   It is the UTM zone 11.
11.   The UTM coordinates for the bottom left corner of the map are 3763000 northing; 361500 easting.
12.   There is 1 km2 in each square, or 1,000,000 m2.
13.  
14.   The magnetic declination of the map is 14o.
15.   The water flows South, since the elevation given by the Contour lines is decreasing.

16.