1 of 6 8/3/2007 1:54 PM Project 1: Plotting Coordinates and Projections Dan Uhrhan dfu101@psu.edu
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5 of 6 8/3/2007 1:54 PM [Replace the example map shown above with one you create using the Interactive Album of Map Projections. Like the sample map, yours should highlight the location of your home town. Feel free to select your own map projection or projections, however, and show distortion ellipses if you wish. After you've replaced the sample map, replace this text with your own description of the map projection you created. State which geometric properties of the globe (i.e., sizes, shapes, distances, and directions) your projection preserves, and which it distorts. If you choose to show only a portion of the globe that frames your particular country or region of interest, specify the bounding coordinates used.] Geographic Coordinates The place name shown on the map above represents the location of my home town, Columbia, IL, located at the geographic coordinates: Latitude: 38.4436637, Longitude: -90.2012239 This is in decimal degrees formatting. For the purposes of the project, I used the decimal degree format indicated by the United States Geological Survey (USGS) Geographic Names Information System (GNIS) and converted to degrees, minutes, seconds (DMS) format with the remaining decimal places included. In DMS format, the same location would be shown as: Latitude: 38 26' 37.18932" N, Longitude: 90 12' 4.40604" W I used the DMS with decimals as I wanted to get precise and accurate results. [Describe the geographic coordinate system in your own words. Why are latitude and longitude coordinates expressed in degrees rather than distance units? Are latitude and longitude coordinates projected? If so, how? How does the concept of a "horizontal datum" relate to the geographic coordinate system?]
6 of 6 8/3/2007 1:54 PM UTM Coordinates The UTM coordinates of Columbia, IL are: (NAD27) Easting: 744265.725 meters, Northing: 4258546.518 meters, Zone: 15 (NAD83) Easting: 744259.549 meters, Northing: 4258753.141 meters, Zone: 15 [Describe the UTM coordinate system in your own words. Why are eastings and northings expressed in meters rather than degrees? Are UTM coordinates projected? How? How does the concept of a "horizontal datum" relate to the UTM coordinate system?] National or Regional Coordinates The State Plane coordinates (SPC) of Columbia, IL are: (NAD27) Easting: 490102.486 feet, Northing: 647013.374 feet, Zone: 1202, Area: IL W (NAD83) Easting: 696983.308 meters, Northing: 197214.488 meters, Zone: 1202, Area: IL W [Describe your national or local coordinate system (State Plane Coordinate system or other) in your own words. Why are eastings and northings expressed in meters rather than degrees? Are SPC coordinates projected? How? How does the concept of a "horizontal datum" relate to SPC coordinates?] [Finally, compare and contrast the three coordinate systems in your own words. Why are some coordinates projected and others not? What geometric property is preserved in projected coordinate systems, and why? Explain the difference between NAD83 and NAD27. Why are different horizontal datums in use?] Sources [Edit as appropriate] National Geodetic Survey (no date) NADCON - North American Datum Conversion Utility. Retrieved 7 July 2007 from http://www.ngs.noaa.gov/tools/nadcon/nadcon.html National Geodetic Survey (2004). SPC Utilities. Retrieved 30 July 2007 from http://www.ngs.noaa.gov/tools/spc.html National Geodetic Survey (2004). UTM Utilities. Retrieved 30 July 2007 from http://www.ngs.noaa.gov/tools/utm.html United States Geological Survey (2006). Geographic Names Information System. Retrieved 30 July 2007 from http://geonames.usgs.gov [Use this to find geographic coordinates for U.S. locations.] United States Geological Survey (2006). Map Projections Poster. Retrieved 7 July 2007 from http://erg.usgs.gov/isb/pubs/mapprojections/projections.html [More information about projections here.] Penn State Online GIS Education (2005). Interactive Album of Map Projections. Retrieved 30 July 2007 from http://projections.mgis.psu.edu This document is published in fulfillment of an assignment by a student enrolled in an educational offering of The Pennsylvania State University. The student, named above, retains all rights to the document and responsibility for its accuracy and originality. Page Modified: August 3, 2007 Page Modified: July 9, 2007