Using Maps and Mapping Technology

Map Projections

• Video Clip (approx 3 min)

• An attempt to portray the round - “spherical” Earth on a flat surface– Creates large areas of

distortions

• There are three common projections

Mercator Projection

• Features of Earth depicted in the form of a cylinder, stretched out on paper – usually a rectangular map

• Most accurate at point of contact – the equatorial areas

• Distortions away from point of contact - near the poles

Conic Projection

• A way of mapping the Earth in the shape of a cone ---point of cone situated directly over one of the poles

• A “birds-eye view” of the Earth

• Most accurate at point of contact - mid-latitudes

• Distortions away from point of contact - poles and equatorial areas

Polar Projection

Portraying Earth or a portion of the Earth in a circular map

Most accurate at point of contact – the poles

Distortion further from the point of contact – mid-latitudes or equatorial area

Topographic Map• Shows surface surface

featuresfeatures or topographytopography of the Earth

• Shows – natural and artificial

features (fields, forests, rivers, lakes, glaciers, buildings, roads, power-lines, etc.

– elevation (with brown contour lines)

• Little to no distortion• Much more later!

Satellite Imagery

• Photographs made by means of artificial satellites

• Most often used:– To predict weather

on Earth– To help create

maps of the seafloor, other planets, topography, etc.

– Military intelligenceTyphoon near Japan

Satellite Image of Earth At Night

Satellite Image of Ocean Depth

Satellite Image – Gulf Oil Spill

GPS “Global Positioning System”

Problems with GPS

• Works poorly in the following areas:– Dense forest– Deep canyons– Caves– Underwater

Latitude & Longitude

Latitude

• Horizontal/parallel lines on a globe or map

• Measure north or south of the equator

• AKA – Parallels

On a map latitude looks like this…

equator

Examples:

• What line of latitude runs through Canada?

equator

Examples:

• What line of latitude runs through Florida?

equator

Longitude

• Vertical lines on a globe or map• Measures east or west of the prime meridian• AKA - Meridians

On a map longitude looks like this…

Prim

e m

erid

ian

Inte

rnat

iona

l Dat

e Li

ne

Examples

• What is the longitude for the middle of S. America?

Prim

e m

erid

ian

Inte

rnat

iona

l Dat

e Li

ne

Examples

• What is the longitude for California?

Prim

e m

erid

ian

Inte

rnat

iona

l Dat

e Li

ne

Putting it together…• What are the coordinates for the following

– X– Y– Z

z

yx

PM

EQ

IDL

Map Scales

• Verbal Scale– Example 1 inch = 1 mile

• Representative Fraction (R.F.)– Example 1:24,000 (1 map unit is

equivalent to 24,000 land units.)

• Graphic Scale– Example

Map Symbols