Assignment #3

Map Projection

1.) Mapping the world For assignment 3, I have used World Winkel Tripel Projection system to project map of the world. This projection is used for world maps to minimize shape and area distortion. It has been used by the National Geographic Society since 1998 for general and thematic world maps. It is a compromise projection used for world maps that averages the coordinates from the equirectangular (equidistant cylindrical) and Aitoff projections. This was developed by Oswald Winkel in 1921. Modified azimuthal—coordinates are the average of the Aitoff and equirectangular projections. Meridians are equally spaced and concave toward the central meridian. The central meridian is a straight line. Parallels are equally spaced curves, concave toward the poles. The poles are approximately 0.4 times the length of the equator. The length of the poles depends on the standard parallel chosen.

Figure 1: Mapping using World Winkel Tripel NGS Projection 2.) Mapping the United States In this exercise, map of the United States showing states was selected. The properties of U.S cities was modified using “Query Builder” such that the capital cities of each state is considered with population greater than 10000. Symbology was edited and each capital cities were labeled. After that, the distance between two cities was measured using “Measure” tool in toolbar and “Magnifier” option in windows tool in toolbar. Later, for the same was introduced. The map was projected using USA Albert Equal Area projection. After the projection was completed, the distance between same two cities was measured. The distance between same cities were found different for two different maps, one with projection and other without projection. Finally, a map of United States was created featuring capital cities, displayed based on population, projection used and proper legends and scales.

Figure 2: 48 contiguous state U.S map without projection

Figure 3: 48 contiguous state U.S map with USA Albers Equal Area projection

a. Determine the approximate and of three cities. Ans. City Longitude (Decimal Latitude (Decimal Degrees) Degrees) Phoenix -111.997187 33.353828 Carson City -119.775439 39.072482 Raleigh -78.802006 35.766336

b. What is the distance between Augusta and Olympia in miles if the view is not projected? Ans. The distance between Augusta and Olympia in miles if the view is not projected is 2530.379 miles.

c. What is the distance between Augusta and Olympia in miles if the view is projected into Albers Equal Area? Ans. The distance between Augusta and Olympia in miles if the view is projected into Albers Equal Area is 2547.810 miles.

d. In the Cities attribute table, why do think there are several values with –99 when looking into the elevation values? Ans. The number of -99 in elevation data changes with different projection. There are -99 in elevation values because of datum transformation. The datum changes with each projection.

e. What are the same distances in kilometers? Ans. Without projection, the distance in kilometer is 4072.259 km and the distance is 4100.312 km When projected.

f. Which capital city is the most populous? Ans. Phoenix is the most populous city with population of 983403.

g. Which capital city is the least populous? Ans. Montpelier is the least populous city with population of 8,247.

h. Which capital city has the highest elevation? Ans. Santa Fe has the highest elevation. The elevation is 6989 ft.

Figure 4:Map of USA with capital cities displaying population variation

3.) Mapping New Mexico Here, state of New Mexico was selected for U.S map showing different states. The selected state was exported as a different file and then later projected using “Project” tool in ArcToolbox. For projection, USA Contiguousa Albert Equal Area projection was used with -106 central meridian. Final maps was created featuring state of New Mexico, United States, world map using the selected projection and including projection parameter.

Figure 5: Map of New Mexico with projection parameter