Overview
Topographic maps are used extensively by a variety of people including geologists, field biologists, and hikers. A topographic map is the representation, on a flat surface, of part of the Earth's surface drawn to scale.
Topographic maps show the shapes and features of the Earth's surface. A contour line connects places on the map which have the same elevation. To demonstrate the different elevations shown on a two dimensional topographic map, you can build a 3-dimensional model.
This is an excellent opportunity for an orientation exercise: the students are asked to orient the model to the outdoor reality. As a group, we computed the scale (approximately 1:14,000) of the model by using ratios and proportions and a 1:24,000 topographic map of the Ramona area (USGS's San Pasqual 7.5 minute quadrangle). It works best when you use enough topographic maps of the area so that each group of students has a copy. It would be especially interesting to make topographic models of several different areas in the local quadrangle and line them up as they would appear if the students were flying a plane over the area.
Using aerial photos, the program VistaPro, DEMs (digital elevation models), and topographic maps, students explore their local area, Mount Shasta and various locations on Mars to learn more about some of the different ways geographical data can be represented.
Using a digital aerial photo of the Ramona area (from Aerial Photobank), the students were asked to find Mt. Woodson. This is a little bit more difficult than you might guess, because with the nadir view, one loses all sense of elevation which acts to camouflage Mt. Woodson. This search for Mt. Woodeson generated some interesting class discussion about camaflage and perspective. After identifying Mt. Woodson, the students oriented the topographic models they created in the first activity to the aerial photograph. They were given time to explore the high resolution aerial photographs of their local area and look for detail and identifiable landmarks.

Goals:
The main goals of this activity are understanding topographic maps and translating data from 2-Dimensions to 3-Dimensions. This activity will help you to visualize, in three dimensions, features represented by contour lines on a topographic map.

Central Question:
How can a two dimensional map represent three dimensions of space?

Materials for each team:
colored construction paper
cardboard spacers (thin cardboard is easiest to cut with scissors)
scissors
glue
Photocopy of topographic map of prominent feature near your school. You may need to enlarge the topographic map.
To locate and order a USGS topographic map of your local area, go to the USGS topographic map site.

Other resources:
Worksheets
Aerial photograph of same prominent feature as in topographic map

Setting the stage:
Begin with an explanation of what contour lines represent. Remember, if they are close together, the terrain is steep, and if they are far apart, the terrain is flatter.

Exploration/Investigation
Working as a class, you can complete the first set of questions (about Map #1) as a group in order to be certain that the students understand the concepts.

Split into groups of three to four (three is the best number to be sure that everyone will have a job to complete and be working.) This goes quickly is students work together efficiently, one tracing and two cutting. Glue layers together at the end, after all the pieces are cut out. Make certain that the orientation of the model matches that of the topographic map. We ran off one extra copy of the topographic map per table so the students could check their work before glueing.

Bringing it together:
Class discussion
Determine the scale of the model as a class. If the feature is visible from the classroom, you can have the students orient their model to it. Using the model and the topographic map, the students can determine the cardinal directions.

Assessment:
Completion of model
Questions

Background:
Topographic maps are used extensively by a variety of people including geologists, field biologists, and hikers. A topographic map is the representation, on a flat surface, of part of the Earth's surface drawn to scale.

Relief is the difference in elevation between any two points. Where relief is low, the area appears to be relatively flat as in river valleys or broad, flat uplands. When relief is high, the area is steep, as in rugged mountainous terrain. Relief determines the contour interval, which is the differences in elevation between adjacent contour lines. A contour line is an imaginary line on the Earth's surface connecting points of the same elevation. Contours can be large for rugged terrain (80 or 100 feet) or they may be small in areas of low relief (10-20 feet). Contour intervals are consistent for a given map, though they may change from map to map. Usually every fifth contour line (an index contour) is printed heavier than the others and bears the elevation above sea level.

In addition to contour lines, heights of many points occur on the map, such as road intersections, summits of hills, lake shorelines, etc. These are spot elevations and are accurate to within the nearest foot or meter. More precisely located and more accurate in elevation are bench marks, points marked by brass plates fixed permanently on the ground. On a topographic map, bench marks are represented by crosses and the elevation, preceded by the letters "BM", is printed in black on the map.

Activity Sheets:
Student Activity sheet can be downloaded and printed from HERE.