TEACH!: Unit 2, Lesson 1.


Rocks, Ice and Dirt:

The Shape of the Land:
An Introduction to Topographic Maps

Objective:

The participants will understand the basic vocabulary
and interpretation of topographic maps.

Supplies:

Background

Maps are drawn as a representation of the earth. On a topographic map, the shape of the earth’s surface is depicted with contour lines. Contours are imaginary lines that join points of equal elevation and provide information about landforms. The difference in elevation between two contour lines is called the contour interval. In flat terrain there is a large distance between contour lines, while in steep terrain there is a small distance between contour lines.

Looking for contour line patterns can help your students identify landforms. The following three contour line patterns are particularly helpful: 1) a hill or mountain peak will have a concentric circle pattern, 2) a cliff will have contour lines very close together, and 3) a drainage or stream bed will have several V-shaped contour lines in a row.

Take a look at a topographic map of French Creek State Park (Click here). It has many of the features typical of most topographic maps, including elevation, hilltops, rivers, lakes, and cultural features. Topographic maps, such as this one, clearly demonstrate how rivers and streams flow from areas of high elevation to lower elevation. As an example, trace the path of French Creek as it flows from Hopewell Lake down through the surrounding landscape. Pine Creek is another good example, starting at an elevation of 650 m and then flowing down hill.

Activity

1. A good way to introduce topographic maps is to create a map on your hand using a ball-point pen. Mention that topographic maps have contour lines and a specific contour line marks a line at the same elevation.

2. Draw several contour lines around your knuckle while keeping your hand in a fist. The lines should look like concentric circles.

3. Draw contour lines on two adjacent knuckles.

4. Show the students what the contour lines look like from a 3-D perspective (your hand in a fist). Then flatten your hand and show the contour lines from a 2-D perspective (your hand out stretched), the same perspective as a topographic map. You can also point out that your knuckles are like a mountain peak or top of a hill and the corresponding contour lines have the typical concentric circle shape.

5. You can now practice basic topographic map reading. Hand out maps of your site (or some other interesting place you may visit in a future class) and have students work in pairs.

6. First, discuss the map colors; there are shaded colors and line colors. The shaded map colors have the following meanings: blue denotes water, green denote s tree cover, white denotes non-tree cover, and grey or red denotes densely built-up areas.

7. Next, discuss the line colors and note that lines may be straight, curved, solid, dashed, dotted, or in any combination. The line colors have the following meanings: blue denotes hydrographic features (i.e. lakes, streams, irrigation ditches). Red denotes map grid lines and important roads. Black denotes cultural features (i.e. smaller roads, trail s, railroads, buildings, boundaries). Brown denotes contour lines.

8. Have students find as many of these features on the map as they can.

Resources

Pennsylvania Department of Conservation and Natural Resources, Geological Survey –You can download maps of Pennsylvania, including topographic maps of the site where you teach, from a variety of sources including Pennsylvania Spatial Data Access (PASDA), Penn State University Libraries, and MapTech.

United States Geological Survey (USGS) –The USGS creates topographic maps. They have many resources on reading maps as well as teaching map-reading skills. Visit
https://pubs.er.usgs.gov for a guide to the symbols used on topographic maps. Visit https://education.usgs.gov for a comprehensive portal to all of the education materials developed by the USGS.


Continue to:
Unit 2, Lesson 2.: “The reason for the seasons”
Go back to:
Unit 1, Lesson 3: Journaling: A journey toward a naturalist’s view


 

Updated: May 2018

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