Earth & Space ScienceChapter 2

Mapping Our World

Mapping the Earth• Latitude

o Parallelo Equator = 0⁰o Poles = 90⁰

• Longitude o Semicircles, not

parallelo Prime meridian = 0⁰ o International Date

Line = 180⁰o 15⁰ = 1 hour

Map projections

• It is difficult to represent the three dimensional Earth on a two dimensional map.

• All maps have distortions. Different types of maps are used for different purposes.

• Map projections:– Mercator– Conic– Gnomonic

Conic and Gnomonic Projections

Mercator projection

•Able to show most of the earth’s landmasses•Distortion increases with distance from equator

Distortion of a Mercator Map

Peters Map projection

Winkel Tripel Map Projection

Topographic Maps

• Hershey kiss map

Rules for Contour Lines

• Contour lines never cross or intersect.• When a contour line crosses a river the “V”

always points upstream. • The slope is steep when the contour lines are

close and flat when contour lines are far apart.

• Contour lines form loops or are lines that go the edge of the map

Sinkholes and Craters

• A depression is shown by contour lines with small “hachures” pointing toward the lowest point.

Match profile and contour map

• A profile is the side view of a land surface between two points on a topographic map representing the shape of the land.

Remote Sensing

• Landsat Satellite: – visible and infrared radiation– Scan Earth’s entire surface in 16 days

• TOPEX/Poseidon– High frequency radar signals– Ocean floor and sea level mapping from satellite

• Sea Beam– Sonar (sound waves) ocean floor mapping from a

ship

GPS and GIS

• GPS (Global Positioning System):• Satellite navigation system• Airplanes, ships, cars, phones

• GIS (Geographic Information System): • Layering different types of maps