Map Properties and Projections

Maps

  • Maps are a language of geography.
  • Cartography is the science or art of map-making.

Map Qualities

  • Area (size)
  • Shape
  • Distance
  • Direction

Map Projections

  • Map projections are mathematical transformations to represent the curved Earth on a flat map.
  • Types of map projections:
    • Cylindrical
    • Conic
    • Planar
    • Mathematical

Cylindrical Projections

  • Mercator Projection (1569)
    • Offers a realistic depiction of shapes.
    • Has distortion problems.
  • Miller Cylindrical Projection

Conic Projections

  • Useful for mid-latitudes where distortion is less.
  • Also good for areas of east-west extent.
  • Lambert Conformal Conic Projection

Planar Projections

  • Also known as azimuthal projections.
  • Severe distortion away from the center.
  • Good for Polar Regions.
  • Azimuthal Equidistant Projection

Mathematical Projections

  • Robinson Projection

Other Projections

  • Fuller Dymaxion Projection
  • Goode's Homolosine Projection

About Projections

  • Conformal Projections - maintain shape.
  • Equal Area Projections - maintain area.

Scale

  • Large Scale: Map equals large detail.

  • Small Scale: Map equals small detail.

    *Designation of Large or Small Scale is relative not numerically precise.

Numerical Scale Comparison

  • Comparison of the actual distance on the surface of the earth to that same distance as portrayed on the map.

Types of Numerical Scale

  • Verbal – One inch equals five miles.
  • Graphic (bar)
  • Representative Fraction – a ratio 1:240001:24000

Legend or Key

  • A box or area located on the map that provides one with important information about the map.
  • Contains information about colors and symbols in use on the map.

North Arrow or Compass

  • Indicates direction

Map Title

  • Informs one what the map is about.
  • Title should contain all pertinent information, but not too long.
  • If the map topic is subject to change the title should have a date.

Source

  • The source of the map identifies the map maker or publisher and also tells the date of publication.
  • Usually found at the bottom of the map.

Coordinate System

  • Assists in locating.
  • Many types:
    • UTM
    • State Plane
    • Military Grid Reference System
    • Geographic Grid

Latitude

  • Lines or parallels that are aligned East to West and are measured in degrees North and South from the Equator.
    • Equator 0°0°
    • Tropic of Cancer 23°30’N23°30’N
    • Arctic Circle 66°30’N66°30’N
    • North Pole 90°N90°N
    • South Pole 90°S90°S
    • Antarctic Circle 66°30’S66°30’S
    • Tropic of Capricorn 23°30’S23°30’S

Longitude

  • Lines or meridians that are aligned North to South and are measured in degrees East and West from the Prime Meridian.
    • Prime Meridian or Greenwich Meridian 0°0°
    • International Date Line ~180°180°

Prime Meridian

  • 00 Degrees Longitude

Equator

  • 00 Degrees Latitude

Other Properties

  • Border or neatline: Encloses the map and all of its information.
  • Insert Map: Provides more detailed information about the main map.