Chapter 2: Portraying Earth

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Chapter 2 Portraying Earth

• Key Concepts

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The Nature of Maps

• Basic Attributes of Maps
• show spatial relationships
• depict graphically where, sometimes why
• Basic Fault of Maps
• 2 dimensional view is inaccurate

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The Matter of Scale

• Scale ratio between distance on map and
  distance on Earths surface.
• Scale Types
• Graphic
• Word
• Fractional
• Large and Small Scale Maps

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Which is more useful, a graphic scale or a
fractional scale? Why?

• Only graphic has legend change as the map changes
  when enlarging/reducing.

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The Role of Globes

• Advantages
• correct geometric relationships
• show comparative distances, comparative sizes,
  and accurate directions
• no distortion
• Disadvantages
• size
• cumbersome

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Map Projections

• Purpose place rounded surface on a flat display
• Ways to lessen the distortion
• arrange grid system
• interrupt the map
• use standard meridians
• The Major Dilemma Equivalence vs. Conformality.

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Interrupted Projection
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Which projection is correct?
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Isolines

• Device for showing spatial distribution.
• Refers to any line that joins points of equal
  value.
• Common types of isolines
• Contour line
• Isobar
• Isohyet
• Isotherm

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Drawing Isolines
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Use of Isolines
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Basic Characteristics of Isolines

• Closed lines, having no end.
• Represent gradations in quantities.
• Maintain a constant interval between them.
• Closeness depends on gradient (slope).

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Distinguish between GPS GIS.

• (GPS) Global Positioning System
• provides accurate longitude latitude
• based on satellite system atomic clocks
• Uses
• deliveries
• navigation
• farming

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Global Positioning System
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Distinguish between GPS GIS.

• (GIS) Geographic Information System
• Spreadsheet for cartographers
• data presented in layers
• layers can be turned on off individually
• allows for comparisons

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Geographic Information System