Office HoursTue: 12:30 PM to 2:30 PMWed: 9:00 AM to 10:30 AM & 12:00 PM to 2:00 PMThr: 9:00 AM to 10:30 AM
Course Syllabus can be found at:
http://www.wx4sno.com/portfolio/BSU/Fall_2011/
This lecture will be posted AFTER class at:
http://www.wx4sno.com/portfolio/BSU/Fall_2011/Lectures/
Lesson 9Topographic 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 Profile1. 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
2. If a computer program is not available, lay a piece of paper down along line AB
3. Start from point A: wherever a contour line intersects the edge of the paper, place a short tick mark AND write down the elevation
4. 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.5. Next, transfer your paper with the tick
marks, elevation, and features to a chart (will be provided)
6. Align your writing along the bottom of the chart
7. Start at point A: transfer your measurements along the X and Y-axis’ moving toward point B.
8. Connect the dots9. Finish by adding the locations of mountain
peaks, streams, roads ,etc.
Example 1
Example 1, cont.
Example 1, cont.
Snowville TopoUsing the Snowville topographic map
from last week, construct a profile along line AB.◦ You may use your printout, or come up to
the screen◦ 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
Once you are done, raise your hand and I will check your work
Snowville TopoLet’s see how our hand-drawn
profile compares to a computer-generated image.
http://www.geocontext.org/publ/2010/04/profiler/en/
Vertical ExaggerationIn our previous example, the y-axis
intervals were the same as the elevation contours on the Snowville topographic map
In our case, the vertical scale we used matched the horizontal scale◦ The vertical scale was equal to the graphic
scale which was given in the lower-left corner
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, con.t
Vertical Exaggeration, cont.To determine the amount of V. E.,
simply divide the horizontal distance (i.e., the denominator of the fraction/ratio) by the vertical distance 1” represents on the graph
Vertical Exaggeration, con.tFor the Snowville topographic profile:
◦ The scale of the topographic map was ½” = ~500’
Converting this and you have 1” = ~1000’
◦ The vertical distance on the graph was 1” = ~1000’
◦ 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)
