Topography of the Earth

Aim: How is Earth’s topography represented on a map?

Objectives:

Read topographic maps Determine elevation and gradients

on the map Create your own topographic map

Vocabulary:

Topography Contour Lines Contour Interval Slope Gradient Depression Altitude Elevation River

A. Topography is….

The shape of the land (flat, sloping, hilly, mountainous)

B. Some more definitions…

Contour line: A line that connects areas of equal elevation on a map

Contour interval: the difference between one contour line and the next.

To find the contour interval, subtract the two values given,and then divide by the number of lines you need to go from one value to the next.

Slope: the angle of the land. The closer the contour lines are on a map, the steeper the slope

Contour Gradient or Elevation Gradient: the rate at which the slope of land changes. The gradient can be either steep or gradual.

Gradient = change in elevation distance

B. More definitions continued…

Depression: This symbol is used to show where the elevation goes down, like a hole.

River: a river is usually shown by a wrinkle or bump in the contour lines

Relief: The difference between the highest and lowest point of a fixed area

Landform: geographical feature of an area

C. Factors that determine topography:

a. Elevation -the height above sea level (altitude)

b. Relief -the difference in elevation between the highest and lowest parts of an area

c. Landforms - A feature that is formed by processes that shape the Earth (i.e. weathering, erosion, deposition, tectonic plate movements)

D. Types of Landforms

a. Plain – low flat land, low relief

b. Mountain – high elevation, high relief

c. Plateau – high elevation, low relief

Virtual Contour Maps

http://www.classzone.com/books/earth_science/terc/content/investigations/es0307/es0307page01.cfm

Let’s take a walk up a hill!

We’re now at an elevation of 100 meters.

100m

Let’s keep going!

100m

Now we’re at 200m.

100m

200m

Shall we march on?

100m

200m

We’ve made it to 300m!

100m

200m

300m

On to the peak!

100m

200m

300m

We’re on the peak, but what’s our elevation?

100m

200m

300m

Any ideas?

100m

200m

300m

Let’sadd contour lines for every 50 meters and see if that helps.

100m

200m

300m

We know that we are above 350m, but less than 400m.

50m

150m

250m

350m

100m

200m

300m

Let’s head down the hill, it’s getting late!

50m

150m

250m

350m

100m

200m

300m

Now what’s our elevation?

50m

150m

250m

350m

If you said somewhere between 200m and 250m you are right!

100m

200m

300m

Let’s try this again!

50m

150m

250m

350m

100m

200m

300m

What’s our elevation now?

50m

150m

250m

350m

If you said 50m or just under, you’re right!

Each color change represents a 50 meter increase.

Now, let’s try the same hike! Our elevation is 0 meters.

Now what is our elevation?

If you said more than 150 meters, but less than 200 meters your

right!

Let’s go a little higher.

Think you know our elevation now?

More than 300meters

But less than 350meters

If we were standing on the peak, what would be our elevation?

More than 350 meters, less than 400

meters

Let’s head down hill.

Know our elevation?

More than 100 meters,

less than 150 meters

Figure 1:

Highest elevation =

Contour Interval =

Elevation of the outermost line =

1. The contour interval is ___________________

2. Which direction does the river flow? ________________

3. Elevation of points:

A ______ B ______ C ________ D ______ X ______

Figure 2…

A

D

B

C

E