Topographic Profiling -DeMarco

The first step: Strike a line across the feature that you would like to profile. It is possible that this may already be done for you. -The line will probably be referred to as Line A-B or Line A-A’

Notice line AB

So, if we were to look at a profile view of line AB on our topographic map, what might we expect to see? Predictions? Time to FIND OUT! Step 2

Take out a piece of scrap paper

Make a small tick at A and B

Make a small tick where each contour line crosses AB

Label each tick mark with the correct value!

Make the X-axis exactly as long as line AB. Label it as “distance”

Next, decide what the HIGHEST and LOWEST elevation values are that line AB crosses on your topographic map and create a scale. You may wish to increase your scale by the contour interval on the map to make things easier. In this case, we are going up by 10’s, because our contour interval on the map is 10 meters.

Remember Labels and Units!

Hold your scrap paper page up to the profile.

Transfer the tick marks directly onto the profile.

straight edge may help

connect the dots!

This is what you might expect the “profile” or cross section view of line AB to look like!

Does it make sense. SURE. There is a creek flowing through this region Does it make sense? SURE! There is a creek flowing through this region. Think about where it would flow on your profile. We also recognize the V shaped contour lines that indicate the direction of water flow.

Or… if you are lucky enough to be able to do your profile on the same page as the topographic map… You can use the: “Drop down a dotted line” method! Example

Same idea, but no need for tick marks and scrap paper!

Gradient Now lets figure out the gradient or steepness of the map between POINTS C & D. GRADIENT= CHANGE IN ELEVATION DISTANCE

Gradient Gradient Between C & D= 310-230 = 80 = 26.7 meters/km 3 3

YOU DID IT!

THE END Special thanks to Charles Burrows… some of the images are from his website.