Measuring the Landscape
We are going to use Google Earth to look at Montana landscapes from above. Before going further, you may want to review some examples of different landforms (landform examples are available in several different formats – they all include the same examples):
- Landform Examples Web Format (can also be accessed using the dropdown menu at the top of the screen or the sidebar menu at the right)
- Landform Examples Powerpoint Format
- Landform Examples pdf Format (does not include notes)
You will also want to download this Google Earth kmz file (IMPORTANT: In some web browsers, you will need to right-click on this link and choose “Save Target As”). Once you have downloaded the file, you can “Open” it in Google Earth. The locations of the landform examples listed above will now be displayed in Google Earth, and you can double click on the stars next to each location to zoom in and single click to open a window describing that location.
Use the Google Earth navigation tools to cruise around southwest Montana and find an example of each of the following:
- Fault block valley
- Glacial valley
- Cirque
- Arête
- V-shaped valley
- Alluvial fan
Challenge yourself and find:
- Meandering river
- Continental divide
- A horne (look it up!)
- A glacial moraine (ditto)
Observations to make for each feature:
- Describe profile shape
- Measure topographic relief
- Measure gradient or slope
- Measure width to height ratio of feature
Also refer to this Lesson Plan on Examining Earth’s Relief (pdf) using Google Earth to create topographic profiles.
On Paper
A great way to observe and record the shape of a landscape is to create topographic profiles. We start with topographic maps which represent a view of the earth’s surface from above. A topographic profile is a cross-sectional view along a line drawn across a topographic map.The condensed version of how to do this is:
- Lay a strip of paper across a map in an area of interest.
- Mark on the paper the exact place where each contour line, stream and hill top touches the strip.
- Label each mark with the elevation of the contour it represents.
- Prepare a vertical scale on another sheet of paper drawing a series of horizontal lines corresponding to the elevations of each contour line. You should use the same scale as the topographic map.
- Place the paper with the labeled contour lines at the bottom of the paper and project each contour to the horizontal line of the same elevation.
- Connect the points.
Of course, the process is more nuanced than that. The next two pages of the Module include videos illustrating how to complete a topographic profile.
Here are some factors you may consider measuring:
- Lowest and highest elevation
- Local relief
- Topographic gradient
- Stream gradient
- Valley shape
- Ridge shape
Demonstration of How to Make a Topographic Profile
Demonstration of How to Draw a Long Profile
