LAB 2 - TOPOGRAPHIC MAPS Key Q- How can a flat map show a 3D feature and its elevation?

LAB 2 -TOPOGRAPHIC MAPS

Key Q-How can a flat map show a

3D feature and its elevation?

Contour lines are lines drawn on a map connecting points of equal elevation.

(If you walk along a contour line you neither gain or lose elevation)

Picture walking along a beach exactly where the water meets the land.

The water surface marks an elevation we call sea level, or zero.

Contour lines are useful because they allow us to show the shape of the land surface (topography) on a map. 

The two diagrams below illustrate the same island.

The diagram on the left is a view from the side. 

The diagram on the right is a view from above such as you would see from an airplane flying over the island.

Surveyors carefully measure the land and study ariel photos to create a topographic map

From the map (and the profile) we can see that this island has two "high" points. 

– The highest point is above 30 ft elevation (inside the 30 ft contour line)

– The second high point is above 20 ft in elevation, but does not reach 30 ft

READING ELEVATIONSA common use for a topographic map is to

determine the elevation at a specific location. 

Each of the letters represent elevated locations.

Use the map and determine the elevation of each of the 5 points. (Assume elevations are in feet)

POINT A = 0 ft

POINT B = 10 ft

POINT C = ~15 ft

POINT D = ~25 ft

POINT E = ~8 ft

The spacing between contour lines is referred

to as the contour interval. 

In areas with high relief the contour interval is

usually larger to prevent the map from having too

many contour lines.

Determine the contour Interval on this map and

find the elevation at…

Point A = 700 Point B = 740 Point C = ~770 Point D = 820

Close contour lines indicate that elevation changes rapidly.

Close contour lines = A steep slope

Geologic Maps

Show rock type, age and

distribution

Topographic Maps can use color to show the geology of an area (Geologic Map)

Analyze the map on page 10 in your textbook

What are the words in the legend referring to?

Rock Type

Age of Rock

(Geologic Time)

Brain Pop- Geologic Time

Topographic Maps can use color to show the geology of an area (Geologic Map)

Analyze the map on page 10 in your textbook

•What area do you think this is a map of?•What are the most common rocks on this map?•Do certain rocks border other rocks? Give 2 examples•Is there a pattern between rock age and type? Explain•Is there a pattern between elevation and rock type? Explain

3. CARTOGRAPHERa person who makes maps

6. CONTOUR INTERVAL the difference in elevation between two contour lines

(FLAT area = SMALL contour interval)

(STEEP area = LARGE contour interval)

7. CONTOUR LINE

a line that connects points of the same elevation (curved

lines)

10. ELEVATIONthe height of land above sea

level

34. TOPOGRAPHIC MAPa map that shows the shape and elevation of landforms from above

35. TOPOGRAPHY the shape of the physical

features of the land surface