Maps• What are they?

• What do they tell us?

• What is map scale (large & small)?

• What is map projection? How does it impact the impression(s) the maps give the reader?

What Are Maps?

• Maps are two-dimensional representations of all or part of the earth’s surface.

• The are scale models of the earth’s surface that have been simplified to make them readable.

Maps

• Two purposes– As reference tools

• To find locations, to find one’s way

– As communications tools• To show the distribution of human and physical

features

Map Scale

• Map scale shows ratio of the distance on the map to that on the earth’s surface.

• It gives the reader of the map a sense of how much of the earth’s surface is portrayed on the map and also helps determine distances between places on the map.

Maps: Scale

• Types of map scale– Ratio or fraction: 1:24,000 (1 inch on the map = 24,000

inches on the earth’s surface, 1 meter on the map = 24,000 meters on the earth’s surface)

– Written: 1 inch = 1 mile (1 inch on the map = 1 mile on the earth’s surface)

– Graphic:

Large v Small Scale Maps

• The larger the scale of the map, the smaller the portion of the earth’s surface it shows

• The smaller the scale of the map, the larger the portion of the earth’s surface it shows

Examples:

A Washington State map is at a scale of 1:10,000,000

A map of downtown Seattle is at a scale of 1: 10,000

Smaller Scale

Larger Scale

Projection

• Map projection is the way in which a portion of the earth’s surface is transferred to a map.

• The problem is that the earth is basically spherical while maps are flat, thus there is going to be some sort of distortion on the map.

Issues with map projections

To some extent all maps have issues with the following:

• size

• shape

• distance

Mercator

Robinson