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565 Project Options

565 Project Options. Annotated Bibliography 10-page Term Paper (report) Original Mapping Mashup Professional Map Research Poster Mapping Website Mobile GIS Application . Geography of a Recession.

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565 Project Options

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  1. 565 Project Options • Annotated Bibliography • 10-page Term Paper (report) • Original Mapping Mashup • Professional Map • Research Poster • Mapping Website • Mobile GIS Application

  2. Geography of a Recession Unemployment in the US has increased from 4.5% in January of 2007 to 9.5% in February of 2011. The hardest hit areas are the southern coastal regions while the north-central region has seen the smallest impact. http://bit.ly/3xsef0

  3. Longley • Chapter 1 – GIS • Chapter 2 – Applications • Chapter 5 – Georeferencing

  4. GI-Science Is About • Acquiring Spatial Data – representing things on the earth • Evaluating – making sure data fits use • Analysis – turning data into information • Cartography – the creation of maps • Dissemination – distributing maps and results • Documenting – ensures future use

  5. Software People Data Network Procedures Hardware Geographic Information System • Organized collection of • Software • Hardware • Network • Data • People • Procedures

  6. Forestry Wildlife Geology Spatial Management Navigation Transportation Security Atmospheric Sci. Oceanography Anthropology Biogeography Environmental Sci. Tourism Economy Policy Social Science And more… General GIS: Data acquisition, management, analysis, and representation Basic concepts, skills, knowledge

  7. Major Questions for a GIS: • What exists at a certain location? • Where are certain conditions satisfied? • What has changed in a place over time? • What spatial patterns exist? • What if this condition occurred at this place? (modelling, hypothesis testing)

  8. Coordinate (or Spatial) Reference Systems • Datum – shape of the earth • Can contain a Spheroid • Coordinate System • Cartesian or Rectangular • Spherical • Projection – How to convert 3D to 2D • Geographic or Un-projected • UTM • State Plane

  9. What is a datum? • Baseline • Typically the average sea level • Also a “vertical reference” BLM

  10. Earth is a big bag of molten lava spinning out its axis 12, 756 km Molten Lava 12, 714 km

  11. People have been estimating datums for centuries • There are hundreds of datums • Now we have satellites & know the shape of the earth www.nasa.gov

  12. Datums • If you only work in the US, 98% of the time you will be using: • North American Datum 1927 (NAD 27)‏ • North American Datum 1983 (NAD 83)‏ • World Geodetic System 1984 (WGS 84)‏ • High Accuracy Reference Network (HARN) • Important point: • There is a datum shift between NAD 27 and all the others • Lots of US agencies still use NAD 27!

  13. Geographic Coordinate Systems • Spherical coordinate system • Units are in degrees • Rectangular coordinate systems • Units are in linear units: • Kilometers, meters • Miles, feet • Nautical miles, fathoms

  14. Spherical Coordinates Point of Interest • Longitude: Degrees East or West from the prime meridian • Latitude: Degrees North or South from the Equator Latitude Longitude

  15. Longitude: -180° to 180° -180° 180° North Pole WEST -90° 90° EAST Prime Meridian 0° Polar View

  16. Longitude: 180° W to 180° E 180° W 180° E Pole 90° E EAST 90° W WEST Prime Meridian 0° Polar View

  17. Longitude: 0° to 360° 180° Pole 90° EAST 270° WEST Prime Meridian 360° 0° Polar View

  18. Latitude: 90° to -90° 90° ~40° Equator 0° -90° Equatorial View

  19. Latitude: 90° to -90° 90° N ~40°N Equator 0° 90° S Equatorial View

  20. Degrees, Minutes, Seconds (DMS)‏ • Each degree contains 60 minutes • Each minute contains 60 seconds • 40° 31’ 21” North by 105° 5’ 39” West • 40 31 21 N, 105 5 39 W • 403121N, 1050539W See the GNIS web site for coordinates of locations in the US

  21. Geographic Accuracy in DMS • The earth is about 40,000 km around • 40,000 / 360 degrees ~ • 111 km/degree • 111 km/degree / 60 minute/degree ~ • 1.85 km/minute • 1.85 km/degree / 60 seconds/minute ~ 0.03 km/second or 30 meters/second • To maintain 1 meter accuracy we need to keep 2 digits after the seconds decimal!

  22. Decimal Degrees

  23. Decimal Degrees • The earth is about 40,000 km around • 40,000 / 360 degrees ~ • 111 km/degree or 111,111 meters/degree • To keep 1 meter accuracy we need to keep 6 or more digits after the decimal!

  24. Finding Coordinates • Go to: http://geonames.usgs.gov/ • Search for a name • What format are the coordinates in? • What is the accuracy of the data?

  25. Problem: • The earth is an oblate spheroid • It’s really hard to find spherical paper! • Answer: • Spend hundreds of years making up thousands of ways to convert spherical data to rectangular!

  26. Cogito Ergo Sum Cartesian Coordinates(Rectangular)‏ • X,Y • Easting, Northing • Miles, Meters, Feet, Nautical Miles Y North X East

  27. Projections http://egsc.usgs.gov/isb/pubs/MapProjections/projections.html

  28. Projections and Distortion • Cylindrical Projection • Lines of longitude are equal-distant • Lines of latitude are greatly distorted at the poles http://standards.sedris.org/18026/text/ISOIEC_18026E_ABSTRACT_CS.HTM

  29. Mercator Distortion

  30. Google Maps

  31. Projections • Area preserving projections • UTM, Lambert Cylindrical Equal-Area • Equidistant projections • UTM, Geographic for North-South • Conformal preserves local shapes • UTM, Lambert Conformal conic

  32. Appropriate Projections

  33. Projections • There are hundreds of projections • 98% of the time you will be using: • Geographic (Un-Projected)‏ • Universal Trans-Mercator (UTM)‏ • State Plane

  34. Global UTM Zones

  35. UTM Coordinate Systems • Universal Trans-Mercator Projection • Line of tangency runs north south • Broken up into 120 Zones (60North/60South)‏ • Each zone has its own UTM projection with line of tangency running up the middle • Minimizes distortion in each zone • Units are in meters

  36. UTM Zones (Northern Hemisphere)‏ 84° N Latitude X 500,000 Easting (X)‏ 4,000,000 Northing (Y)‏ Y Equator 500,000 meters

  37. Be careful! • Don’t use “N” for “North” and “S” for “South”. In UTM the “N” region is in the south and the “S” region is in the north! • Use “North” and “South” • Yes, ESRI uses “13N” for our region!

  38. Global UTM Zones USGS

  39. US UTM Zones USGS

  40. State Plane USGS

  41. State Plane • Each state has one or more zones • Each zone has its own axes and origin • May be based on different projections • Zones usually by county boundaries • Units are in feet

  42. Oregon State Plane

  43. Coordinate (or Spatial) Reference Systems • Datum – shape of the earth • Can contain a Spheroid • Coordinate System • Cartesian or Rectangular • Spherical • Projection – How to convert 3D to 2D • Geographic or Un-projected • UTM • State Plane

  44. Reference System Standards • European Petroleum Standards Group • EPSG • Well Known Text Form • WKT‏ • Arc “projection” files • PRJ (contains entire SRS) • Proj 4 • Projects and performs datum shifts

  45. ArcLand Usage • Spatial Reference System (SRS) • Spatial Reference = SRS • Coordinate Reference System (CRS) = SRS • Horizontal Coordinate System = Horizontal portion of SRS • “Define Projection” = Define SRS • “Project” = Change SRS

  46. GPS • Make sure you set the “projection system” (really just Datum) and don’t change it!

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