Map Reading and Interpretation Contour Lines

Contour Lines

Contour lines are always the same distance apart on a map. 25 feet on this. Not all topographic maps have been converted Contour Interval Is the height difference between any two adjacent contour lines on a map Constant across a map

Reading Contour Lines Elevation of Point A: 25 feet Elevation of Point B: 87.5 feet approximately

Activity: Contour Lines On the map provided, determine the elevation of the following points: Marie Plateau Mount Adams Mount Gould Mount DesBarres Mount Marie

Contours Contour Profile / Cross section Allows the map reader to take a flat, two dimensional map and develop an idea of what the land looks like Questions: Is it steep? Is it flat?

Contour Profiles / Cross Section

To create a profile … Step 1: Mark the contour lines on a small sheet of paper; place the contour height at each marked point (A / B) Step 2: On the side, record a contour value above the highest contour identified (B) and below the lowest contour identified (A). Note: Your map: intervals are 50 feet apart Step 3: On loose leaf, make a scale (Think y-axis). Print the highest value at the top. Number down until you reach your lowest value (This number does not have to be zero)

To create a profile (cont’d)… Step 4: Place the small sheet of paper along the lowest line Step 5: Align the lettered point with the axis line (see below) Step 6: Using the scale (lower line) as a guide, place a dot at the correct height Step 7: Join the dots Result: The map view is converted To a profile view

Purpose of Contour Profile Intervisibility: Profiles allow you to tell whether one point can be seen from another. Question: Profile A to B Is Point B on your map visible from Point A? Can you see the top of the mountain from both points?

On-line Practice http://www.uwsp.edu/gEo/faculty/ritter/geog101/textbook/manuals/instructor_manual/how_to/topographic_profile.html