Maps, Etc. What are they, why do we use them, and how do we use them

Maps, Etc.

What are they, why do we use them, and how do we use them

Globes• 3 dimensional representation of the Earth

• Advantages – exactly as it is, just smaller

• Disadvantages – not easily portable, since it is a sphere, we can only see half at a time

Maps

• 2 Dimensional Representations of Earth, or just a portion

• Advantages: easily portable; can be drawn to any scale

• Disadvantages: DISTORTION – because you are trying to make a round thing flat

Map Projections

• Projections help us overcome/reduce distortion

• Planar (azimuthal) • Conical – shows pretty

accurate shapes and sizes of landmasses, but distorts the edges [good for showing just one big land mass

• Cylindrical – Shows the entire Earth, and there are 3 types

Types of Cylindrical Maps• Mercator – shapes of

continents are distorted at the poles (tops/bottoms), and compressed near equator

• Homolosine – accurate size and shape, but distances are wrong (interrupted)

• Robinson – entire earth, good shapes and sizes, but shape of land at the poles is flat (the one on the wall)

Uses/Types of Maps• General Reference – topographic

• Thematic – specific types of information shown, like climate or population

• Navigation – used by sailors and pilots

Surveying

• This is what you do to gather the info you need to make a map

• It all was manual in the past, now we use satellites and airplanes

Satellite Systems

• Landsat – series of satellites that update the entire Earth every 16 days

• GOES – Geostationary Operational Environment Satellite

More Satellite and Map Stuff

• GIS – Geographic Informational System – this layers information on to a map

• GPS – Global Positioning System – uses 24 Nav Stars to tell you exactly where you are [latitude, longitude, elevation, time]