Understanding Maps- Cartography

The Olde World

Maps vs. Globes 2 dimensional Flat Distorted Shows small details Handy/can fold 3 dimensional Spherical More accurate Shows large details inconvenient

Map vs. Globe

Which is bigger … Greenland, Mexico or Australia

Map Projections Mercator Gnomonic/Azimuthal Conic

MERCATOR PROJECTION Made as if you wrapped a cylinder around a globe Parallels and Meridians appear as straight lines Accurate at equator Distorted at poles

Gnomonic/Azimuthal Projection Made as if paper touched one point on globe Useful for air travel/navigation Accurate at point of contact Uneven spacing between parallels

Conic Projection Made by placing paper cone over globe Cone touches along one parallel Accurate at that point Used for mid latitude navigation Many sections- polyconic

GREAT CIRCLE Any circle that divides the globe into 2 equal halves Useful in navigation Shows the shortest distance between 2 points

Reading a Map LEGEND—symbols used to interpret a map (see p 60) MAP SCALE- indicates the relationship between distance on a map and distance on Earth A) GRAPHIC B) FRACTIONAL C) VERBAL

GRAPHIC SCALE Shows a printed line divided into parts and labeled You can measure distance with a ruler and compare to line

Fractional Scale States the map scale as a ratio Ex.: 1: means one unit on the map equals units on the Earth

Verbal Scale Makes a written statement in words expressing the scale Ex.: “One centimeter equals one Kilometer” Ex. : “One inch equals 5.2 miles.”

They all mean the same thing.

Topographic Map Scales

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