Map Projections and Map Types

All Maps Lie.... Because the world is a sphere and maps are flat, there will always be some degree of distortion.

4 Properties of Maps Shape- refers to the geographic shapes of the objects on the map Size- (area) refers to relative amount of space taken up on the map by landforms or objects on a map Distance- refers to the represented distance between objects on a map Direction- refers to the degree of accuracy representing the cardinal directions

2 dimensional – Maps 3 dimensional – Globes Map Projection-Way of drawing the Earth’s surface by presenting a round earth on a flat surface

Types of Map Projections Equal-area projection- try to space out the distortion equally throughout the map Conformal maps- maps that distort area but keep shapes intact

Cylindrical- shows true direction, but loses distance

Planer- shows true direction and examines the earth from one point (polar projections); also called azimuthal map

Conic- puts a cone over the earth and tries to keep distance intact but loses directional qualities

Mercator Projection Good-Shapes are correct for all areas, and map has correct directional relationships. Bad- Exaggerates lands at the poles Cylindrical

Peters Projection Arno Peters claimed that his map more fairly displayed third world countries than the "popular" Mercator projection map, which distorts and dramatically enlarges the size of Eurasian and North American countries. The media had a field day with this new map that supposedly made things right for the oppressed people of the world.

While the Peters projection does (almost) represent land of equal area equally, all map projections distort the shape of the earth, a sphere. According to prominent cartographer Arthur Robinson, the Peters map is "somewhat reminiscent of wet, ragged long winter underwear hung out to dry on the Arctic Circle." (Monmonier, 10)

http://www.youtube.com/watch?v=n8zBC2dvERM

Robinson Projection Most frequently used. Distorts both size and shape, but not too much. The major benefit of the Robinson projection is that oceans are uninterrupted. This projection is useful in depicting patterns of global interaction.

Types of Maps Political Topographic Navigational Thematic

Political Map Political Maps- show features on the earth that humans created *Show boundaries

Topographic Maps Topographic Maps- general reference map, which is a representation of natural and man-made features on earth *Also called physical maps

Navigational Map Navigation maps- used by pilots and sailors for plotting travel

Thematic Map Thematic Maps- emphasize specific kinds of information Ex. Climate, population density

Types of Thematic Maps

Dot Maps

Isoline Maps An isoline map is a map with continuous lines joining points of the same  value altitude (contour lines), temperature (isotherms),

Choropleth maps Uses colors or patterns

Choropleth map The choropleth map provides an easy way to visualize how a measurement varies across a geographic area or it shows the level of variability within a region. The choropleth map is based on predefined areal units, such as states, counties, census tracts, etc. 

Flow-Line Maps show the movement of information, goods or people between places and the amount being moved Good for showing migration

Cartograms Chart and assign data by size

What does this represent? Infant mortality

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