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Office Hours. Mon: 11:30 AM to 12:30 PM & 1:45 PM to 3:00 PM Wed: 11:30 A M to 12:30 PM Thr : 9:15 AM to 12:30 PM Fri: 10:00 AM to 12:00 P M. Lesson 9. Topographic Profiles Hess, McKnight’s Physical Geography , 10 ed. A3-A4. What is a “topographic profile?”.

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Office Hours

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Office Hours

Mon: 11:30 AM to 12:30 PM & 1:45 PM to 3:00 PM

Wed: 11:30 AM to 12:30 PM

Thr: 9:15 AM to 12:30 PM

Fri: 10:00 AM to 12:00 PM

Lesson 9

Topographic Profiles

Hess, McKnight’s Physical Geography, 10 ed.

A3-A4

What is a “topographic profile?”

• Last week we discussed USGS topographic maps

• 3D landscape on a 2D map

• Use contour lines to connect equal elevation intervals

• This is known as a “plain-view” map

• A topographic profile is literally a “side view” along a line drawn over the topographic map

• They show changes in elevation along a line

Constructing a Topographic Profile

• On the topographic map, determine what profile you would like to measure

• For this exercise & the homework, this is given as the line segment AB

• If a computer program is not available, lay a piece of paper down along line AB

• Start from point A: wherever a contour line intersects the edge of the paper, place a short tick mark AND write down the elevation

• Continue along the line to point B

• Along the way, mark wherever a mountain peak, valley, or stream is located

• Also mark any other important features (roads, buildings, etc)

Constructing a Topographic Profile, cont.

• Next, transfer your paper with the tick marks, elevation, and features to a chart (will be provided)

• Align your writing along the bottom of the chart

• Start at point A: transfer your measurements along the X and Y-axis’ moving toward point B.

• Connect the dots

• Finish by adding the locations of mountain peaks, streams, roads ,etc.

SnowvilleTopo

Example:

• Using the Snowville topographic map from last week, construct a profile along line AB.

• The elevation at point A is 2093

• The elevation at point B is 2085

• Remember to draw both contour lines as “tick marks” AND important features

SnowvilleTopo

• Let’s see how our hand-drawn profile compares to a computer-generated image.

• http://www.geocontext.org/publ/2010/04/profiler/en/

Vertical Exaggeration

• In our previous example, the y-axis intervals were the same as the elevation contours on the topographic map

• In our case, the vertical scale we used matched the horizontal scale

• This brings us to vertical exaggeration

Vertical Exaggeration, cont.

• Vertical exaggeration is created to emphasizes differences in elevation and to show relief

• e.g., when there is a large amount of V. E., small hills appear to be tall mountain peaks on the graph

Vertical Exaggeration, cont.

• To determine the amount of V. E., simply divide the horizontal distance one inch represents by the vertical distance one inch represents

Vertical Exaggeration, con.t

• For the Snowville topographic profile:

• The vertical distance on the graph was

• 1” = ~100’

• The horizontal distance on the graph (not shown) was

• 1” = ~100’

• Divide the horizontal (scale) distance by the vertical distance:

• = 1.0

• Thus the V. E. is 1.0 X (or the same as the horizontal distance)