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  1. 1. Chapter 2: Portraying EarthMcKnight’s Physical Geography:A Landscape Appreciation,Tenth Edition, Hess
  2. 2. Portraying Earth• The Nature of Maps• Map Scale• Map Essentials• The Role of Globes• Map Projections• Families of Map Projections• Isolines2© 2011 Pearson Education, Inc.
  3. 3. Portraying Earth• GPS—Global Positioning System• Remote Sensing• GIS—Geographic Information Systems• Tools of the Geographer3© 2011 Pearson Education, Inc.
  4. 4. The Nature of Maps• 2-dimensionalrepresentation ofEarth’s surface• Show 4 key propertiesof a region– Size– Shape– Distance– Direction• Maps are imperfect, sinceEarth is a sphere4© 2011 Pearson Education, Inc.Figure 2-2b
  5. 5. Map Scale• Maps are always smaller thanthe area they represent• Map scales are necessary tounderstand realistic distanceson map• Scale is relationship betweenarea on map and area onEarth• Three primary types– Graphic– Fractional– Verbal5© 2011 Pearson Education, Inc.Figure 2-3
  6. 6. Map Scale• Large versus small map scales6© 2011 Pearson Education, Inc.Figure 2-4
  7. 7. Map Essentials• Need several propertiesof maps to help withinterpretation:– Title– Date– Legend– Scale– Direction– Location– Data Source– Map Projection7© 2011 Pearson Education, Inc.Figure 2-5
  8. 8. The Role of Globes• Advantages of Globes– Maintains correct geographicrelationships between points– Can accurately represent spatialrelationships between points onEarth• Disadvantages of Globes– Only can see a hemisphere at atime– Large and bulky– Cannot contain much detail8© 2011 Pearson Education, Inc.Figure 2-6
  9. 9. Map Projections• Challenge of the cartographer (“mapmaker”)– Combine geographic exactness of globe with convenience offlat map• Definition of map projection• Principle behind map projections• Two primary types– Equivalent—ratio of areal size on map and Earth is the same– Conformal—shape of locations on the map is the same as onEarth9© 2011 Pearson Education, Inc.
  10. 10. Map Projections• Equivalence versus conformality dilemma10© 2011 Pearson Education, Inc.Figure 2-10
  11. 11. Families of Map Projections• Cylindrical Projections– “Wrap” the globe in acylinder of paper– Paper tangent to Earthat equator– Conformal projection– Mercator projection ismost famous11© 2011 Pearson Education, Inc.Figure 2-7
  12. 12. Families of Map Projections• Plane Projections– Project globe onto apaper that is tangent toglobe at some point– Displays onehemisphere well– Equivalent projection– An example is anorthographic planeprojection (Figure 2-13)12© 2011 Pearson Education, Inc.Figure 2-9
  13. 13. Families of Map Projections• Conic Projections– Project the map onto acone tangent to orintersecting the globe– Principal parallel– Good for mappingsmall areas on Earth– Impractical for globalmapping13© 2011 Pearson Education, Inc.Figure 2-8
  14. 14. Families of Map Projections• PseudocylindricalProjections– A mix of conformal andequivalent– Central parallel andmeridian cross at rightangles– Oval shaped; distortionincreases as you moveaway from the center14© 2011 Pearson Education, Inc.Figure 2-11
  15. 15. Families of Map Projections• Interrupted Projections– Minimize distortion– Discontinuous map,shapes and sizesmaintained– Typically oceans aredistorted; land massesmaintain originalshape and size– Goode’s projection15© 2011 Pearson Education, Inc.Figure 2-14
  16. 16. Isolines• Definition• Many types– Isobar: line of constantpressure– Isotherm: line of constanttemperature– Isohyet: line of constant rain– Isoamplitude: line ofconstant wave amplitude• Construction steps/rules16© 2011 Pearson Education, Inc.Figure 2-16
  17. 17. Isolines17© 2011 Pearson Education, Inc.800700600 500 400300
  18. 18. Isolines• Topographic Maps– Show elevationcontours– Contour lines– Lines closer togetherrepresent steeperterrain– Often used ingeography18© 2011 Pearson Education, Inc.Figure 2-15
  19. 19. Isolines• Topographic Maps– Show elevationcontours– Lines closer togetherrepresent steeperterrain– Often used ingeography19© 2011 Pearson Education, Inc.Figure 2-15
  20. 20. GPS—Global Positioning System• Global navigation satellitesystem for determininglocation on Earth’ssurface• Wide Area AugmentationSystem (WAAS)• Continuously OperatingGPS Reference Stations(CORS)20© 2011 Pearson Education, Inc.Figure 2-19
  21. 21. Remote Sensing• Measurement by a devicenot in contact with Earth’ssurface• Common types include:– Aerial Photographs– Orthophoto maps– Visible Light and Infrared(IR) Scanning– Thermal IR scanning– Radar and Sonar– Many others21© 2011 Pearson Education, Inc.Aerial Photography—Figure 2-20
  22. 22. Remote Sensing• Orthophoto maps– Photographic maps thatare multicolored anddistortion free– Useful in low-lying coastalregions to show marshtopography22© 2011 Pearson Education, Inc.Figure 2-21
  23. 23. Remote Sensing• Visible light and IRscanning– Based off of visible light andIR part of electromagneticspectrum (Figure 2-22)– Shows “false color”23© 2011 Pearson Education, Inc.Figure 2-23Figure 2-22
  24. 24. Remote Sensing• Radar Imagery– “Radio Detection and Ranging”– Useful for identifying atmospheric moisture• Sonar Imagery– “Sound Navigation and Ranging”– Permits underwater imaging• Thermal IR scanning– Scans in the thermal IR part of spectrum– Shows images based on temperature– Often utilized in meteorology24© 2011 Pearson Education, Inc.
  25. 25. GIS—Geographic InformationSystems• Computer systems used toanalyze and display spatialdata• Layers of data used inmapping• Requires high poweredcomputing to processmultiple maps25© 2011 Pearson Education, Inc.Figure 2-29
  26. 26. Tools of the Geographer• Vast array of maps, remotely sensed satelliteimagery, and computer applications• Difficult to determine the best way to use all ofthis information• Some tools better at identifying features onEarth than others• Ultimate goal: “To better understand Earth.”26© 2011 Pearson Education, Inc.
  27. 27. Summary• Maps are essential to portray features on Earth’ssurface• Need a map scale to identify how a map relatesto the actual surface features on Earth• Many other map properties are essential tointerpreting a map• Globes have several advantages anddisadvantages• Representing Earth in 2 dimensions can be donethrough map projections27© 2011 Pearson Education, Inc.
  28. 28. Summary• Many different map projections exist• Dilemma of equivalent versus conformal• Plotting isolines on a map can help withinterpretation of features on the map• The global positioning system (GPS) helps toidentify location on Earth’s surface• Remote sensing is a measurement of Earth’ssurface from a system not on Earth’s surface28© 2011 Pearson Education, Inc.
  29. 29. Summary• Many different remote sensing instrumentsexist, including satellite, radar, and sonar• GIS are computer systems used to analyze anddisplay spatial data, often in layers• The geographer has many tools, but theultimate goal is “To better understand Earth.”29© 2011 Pearson Education, Inc.