LANDFORMS & MAPPINGEarth Science

LANDFORMS

A feature that makes up the shape of the land at Earth’s surface

3 basic types: Plains- large relatively flat areas Plateaus- relatively flat raised areas Mountains- raised areas

WHICH IS THIS?

THIS?

HOW ABOUT THIS?

PLAINS

Coastal Plains Broad areas along

the oceans shore Ex. Atlantic

Coastal Plain Low rolling hills,

swamps, and marshes

Marsh- grassy wetland usually flooded with water

Interior Plains Make up much of

the central portion of the U.S.

Extend from the Appalachian Mountains to the Rocky Mountains

PLATEAUS

Relatively flat, raised areas of land.

Different from plains because they raise steeply from the ground around them.

Ex. Colorado Plateau- lies West of the Rocky Mountains. The Colorado River runs through it forming the Grand Canyon

MOUNTAINS

Folded Mountains Form when rock layers are

squeezed from opposite sides. Ex. Appalachians

MOUNTAINS

Upwarped Mountains Form when crust is pushed up by

forces inside the Earth. Ex: Rockies and Black Hills

MOUNTAINS

Fault-Block Mountains Form when huge tilted rocks are

separated from surrounding rock by faults

Ex Grand Tetons & Sierra Nevada

MOUNTAINS

Volcanic Mountains Form when molten material

reaches the surface and piles up. Ex. Mount St. Helens & Mauna Loa

LATITUDE

Latitude refers to distance north or south of the equator

The equator is numbered as 0 latitude

The poles are each numbered 90

Locations north of the equator are in north latitude and south of it are on south latitude

LONGITUDE

Run north and south around the globe The Prime Meridian is considered to

be 0 longitude All other longitude is measured from

there Longitude goes from 0 to 180 The International Date Line is at 180

longitude

LATITUDE VS. LONGITUDE

TIME ZONES

Earth is divided into 24 different time zones. Each time zone is 15 degrees

(longitude) wide. The US has 6 different time zones International date line

TIME ZONES

MAPS

Maps are all models of some area Maps of the world are commonly

made using projections A projection is made when points

and lines on a globe are transferred onto paper

All projections contain some type of distortions

MERCATOR PROJECTION

Has the correct shape of the continents, but their areas are distorted

When longitude lines are made parallel, the areas near the poles are exaggerated

ROBINSON PROJECTION

Has accurate shapes and shows accurate land mass.

Areas near the pole suffer less distortion

CONIC PROJECTION

Used to produce maps of small areas

Projects points and lines from a globe onto a cone

TOPOGRAPHIC MAPS

Shows the changes in elevation of the Earth’s surface

Shows features such as mountains, plains, lakes, as well as roads, cities, etc.

Allows you to tell how steep a mountain is or how deep a valley.

CONTOURS

Contour line - connects points of equal elevation

Elevation- distance below or above sea level

The difference in elevation between side-by-side contour lines is the contour interval

Contour lines marked with their elevation are index contours

RULES OF CONTOUR LINES

Contour lines close around hills and basins (hachures point down)

Contour lines never cross

Contour lines form V’s that point upstream whenever they cross streams.

WHAT IF MY CONTOUR LINES ARE CLOSE TOGETHER?

If the contour lines are close together, then that indicates that area has a steep slope.

WHAT IF MY CONTOUR LINES ARE FAR APART?

If the contour lines are far apart, then that indicates the land has a gentle slope (low slope).

WHAT DO THE DARK COLORED CONTOUR LINES MEAN?

The dark colored contour lines represent every 5th contour line to make it easier to read the map.

WHAT DO DEPRESSIONS IN THE MAP LOOK LIKE?

A depression, such as the inside of a dead volcano, is represented by Hachure lines.

Hachure lines are regular contour lines with small segments sticking out from it.

The first hachure line is at the same elevation as the contour line before it.

MORE ON CONTOUR LINES

Contour lines form V’s that point upstream when they cross a stream.

It is important to remember that they point in the opposite direction as the flow of water.

WHAT DO THE COLORS ON THE TOPOGRAPHIC MAP REPRESENT?

Blue lines/shapes- represent water features such as streams and lakes

Brown- contour lines Black- roads, buildings, railroads,

other man-made objects Green- woodland areas Red- highways

HOW DO I READ A TOPOGRAPHIC MAP? First determine the contour interval

(the distance between each contour line)

Then determine the map scale (usually at the bottom of the map)

Identify any hills or depressions Use the legend to identify man

made features

READING A TOPOGRAPHIC MAP CONT. Look for areas where the contour

lines are close together- they indicate a steep area.

Look for areas where the contour lines are spread apart – they indicate a gentle slope.

LEGEND AND SCALE

Map legend explains what the symbols used on the map mean.

Map scale is the relationship between distances on the map and actual distances on the Earth’s surface.

Scale is often expressed as a ratio 1:500 means 1 unit

on the map = 500 units on the Earth

MAPPING OUR PLANET

Maps of the world can be made in several ways

Most maps today are made using satellites

Maps of the ocean floor can be made using sonar The Sea Beam is a

very advanced type of sonar device.

SATELLITES

Landsat- detects different wavelengths from Earth’s surface and changes them into color.

Topex-Poseidon- uses radar to find the distance to the oceans surface and plot maps of the ocean floor

GPS (Global Positioning System)- allows a user to determine their exact position anywhere on Earth. Has 24 satellites in

orbit