Aim: How do we read Topographic Maps?

Do Now:

In your notes, list all the different types of landforms/features of Earth that you can think of.

Example: Hills

Topography:

The shape of the land.

K2, PakistanNapa Valley, California

Grand Canyon, Arizona

Topographic Maps: • Represent the shape of the land on a

flat piece of paper.

• Isolines/Contour Lines represent different elevations on a topographic map.

• Each isoline connects values that are equal.

“iso” means equal

m

mm

mm

Altitude:

The height above sea-level or above a specific point on a map.

What value is sea-level?

Get the Altitude worksheet from the back of the room. You and your partner should work on this worksheet together. We will go over it

in 10 min.

a) Index Contour Lines: labeled with the elevation.

Index contour lines

I. Parts of Topographic maps:

Using the index contour lines, determine the value of the lines in

between.

b) Contour Interval:

• Represents a vertical measurement (up hill or down hill).

• Measurement that separates contour lines.

c) Hachure marks:

refer to a drop in elevation (depression/hole in the ground).

d) Bench mark: shows the exact elevation at that point.

Copy diagram into notes

- The first hachured line repeats the same value as the countour line before it.

- The second hachured line counts down by the contour interval.

upstream

downstream

When a river or stream crosses a contour line, the contour line bends and points upstream.

E) River and Streams

• Upstream is where the river starts.

• Downstream is where the river ends.

Closer contour lines = steep slopes.

Further contour lines = gradual slopes.

a) Gradient• Refers to the steepness of the land (slope)

Which side of the hill is the steepest?

WHY?N

II. Calculations on Contour Maps

b) The highest possible point

will always be one unit of measure less than the next possible contour line.

Contour Interval = 10 m

X 10 m

What is the highest possible

value of X?

Closure

Obtain the worksheet called “Reading a Topographic Map” from the back table and complete the worksheet. We will go

over it when finished.