Physical Geology

Chapter 3 Review

• Latitude - The distance north or south of the earth's equator. 0 degrees latitude is the equator, the "belt" that goes around the "waist" of the earth. 90 degrees north is the North Pole and 90 degrees south is the South Pole.

• Lines of latitude (parallels) are blue (north) and red (south) in the drawing.

• 1 degree of latitude equals 1/360th of the earth’s circumference

• That is 111 km

• A degree is divided into 60 minutes

• A minute is divided into 60 seconds

• Washington, D.C., is located at 38 degrees, 53 minutes, 23 seconds North Latitude

• Longitude - Angular distance on the earth's surface, measured east or west from the prime meridian at Greenwich, England.

• Lines of longitude (meridians) are blue (east) and red (west) in the drawing.

• Degrees of longitude are different sizes

• 111 km at the equator, 55 km at 60 N/S, smaller at poles

• 180 degrees E/W is the International Dateline

• Longitude of Washington, D.C., is 77 degrees, 00 minutes, 33 seconds West Longitude

• Give the latitude and longitude of the red, orange, green and pink dots! As you may recall, the latitude lines are shown for every 10 degrees, starting at the equator; the longitude lines are shown for every 15 degrees, starting at the prime meridian. And don't forget, both latitude and longitude are expressed as a certain number of degrees plus a direction - N, S, E or W!

• A great circle is any circle that divides the earth into halves. It is the shortest route between two locations on the face of the earth.

• Used in navigation

Time zones

• Local time measures position of sun in relation to a given position

• Solar noon = sun directly overhead

• 360 degrees of longitude divided into 24 time zones (15 degrees each)

• Zones group population centers so lines vary in places

Time Zones

Finding Direction and Location

• Magnetic compass takes advantage of Earth’s magnetism

• Geomagnetic pole different than the geographic pole

Adjust your compass!

Global Positioning System

• Uses 24 satellites

• Transmit radio signals to the surface

• Any three satellites triangulate position

• Position includes longitude, latitude, and altitude

• Accurate to 10-15 meters OR a few cm

Map Projections

• Cartography/Cartographers

• A flat map that represents the 3-D rounded surface of the earth

• Cylindrical, azimuthal, conic

Projections

Cylindrical

• Surface of globe is projected onto paper cylinder

• Most accurate at point of contact (equator)

• More distortion to N and S

• Still has rigid gridwork for finding locations

Conical

• Most accurate where cone touches globe

• Polyconic uses strips from many conics

• Most accurate form in both size and shape

Azimuthal

• In contact at one point so distorted in all directions from point

• Great circle looks like a straight line

• Great for navigation

Reading a Map

• Name

• Adjacent

• Declination

• Date

• Scale

• Location

• Road Class

Legend

• Symbols used on the map

• Scale

• Direction

Types of Maps

• Topographic

• Geologic

• Soil

• Highway

• Political

• Isograms

Political

PoliticalPolitical

Topographic

Soils

Geologic

Topographic

• Connect equal values

• Can be for temperature, precipitation, magnetism, etc.

• Connect equal values

• Can be for temperature, precipitation, magnetism, etc.

Isogram

Road map or

Highway map