Geographic Coordinates (Latitude/Longitude)

1. Look up the geographic coordinates for the town you were assigned (see: AssignedCifies.pdf) on a. Click Search Domestic Names b. Type in the city in the Feature Name field c. Select the state d. In the Feature Class field, select “Civil” 2. Discuss the global coordinate system (latitude/longitude) a. How does latitude and longitude work? Think about what the important elements of the coordinate system are. Where does it start? b. Why are latitude and longitude coordinates expressed in degrees rather than distance units? c. Are latitude and longitude coordinates projected? If so, how? d. What else is important about latitude and longitude? Convert to Universal Transverse Mercator (UTM) 3. Convert the latitude/longitude (also called geographic) coordinates to UTM coordinates using the National Geodetic Surveys UTM Utilities 4. Coordinates in the Geographic Names Information System have been based on NAD83 since September 2005. (See /domestic/faqs.htm) 5. The UTM utility is very picky about how latitude and longitude must be entered. This is useful; your successful result demonstrates your ability to understand and manipulate such coordinates. Although latitude and longitude coordinates shown as example inputs are given as “N385930.99999”, you can use zero(s) for the five decimal places that the utility allows. 6. Take note of the UTM Northing, Easting and Zone number for your report. 7. Answer the following: a. Describe the UTM coordinate system in your own words. b. Are UTM coordinates projected? c. How many zones are there? d. Where is the origin of the system? e. What makes this different from lat/long? f. What are eastings and northings and why are they expressed in meters rather than degrees? g. Do the UTM coordinates cover the entire globe? h. How many zones are there? i. Are there any disadvantages to using the UTM coordinate system? 8. You may use graphics, but make sure to accurately cite these sources Convert to State Plane Coordinates (SPC) 9. Convert the geographic coordinates to State Plane coordinates using the National Geodetic Survey’s GEODETIC to SPC Utility 10. Take note of the SPC Northing, Easting and Zone name for your project report. Note that the SPC utility reports both ‘m 7nnn Inihrr n

11. You can also look up your SPC zone number and name using 12. Answer the following: a. Describe the State Plane Coordinate system in your own words. b. Why are eastings and northings expressed in meters rather than degrees? c. Are SPC coordinates projected? How? d. Are there zones in this system? e. What are the two projections that are used for SPC? f. How do State Plane Coordinate systems’ projections differ among the 50 US States? Why? Comparison between the three systems 13. Finally, compare and contrast the three coordinate systems in your own words—consider appropriate usage, accuracy, and ease of calculation. Include answers to the following: a. Why are some coordinate systems projected and others not? b. How do the systems compare in terms of accuracy of measurement? c. What geometric property is preserved in projected coordinate systems, and why? d. Compare the systems in terms ability to calculate area and distance measures? Why are some systems better than others? e. When would you use one or the other? Explain these different use cases in terms of scale and mapped location. Part B: Map Projections, comparing Mercator to everything else Even if you look at maps every day, you probably don’t think much about the process of how the globe (a 3D surface) is transformed into a map (a 2D surface).









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