Topographic Maps, contours, and feature recognition
Elevation features are described on maps by use of contour lines. A contour line on a map is the line you would trace out on the terrain if you were to walk along a path of the same altitude (same height or elevation). Every point that you see on a contour line is at the same height as all other points on that same line.
Put simply, here's how some commonly observed terrain features translate into contour lines:
Hills - closed curves of decreasing size. Inner curves are at higher elevation than outer curves, and the peak is within the innermost curve.
Steep hills – rapid drops and rises over short distances are represented by contour lines spaced very close together. For vertical cliffs, the lines will actually converge and over lap as one thick line.
Gentle slopes - slow rises in elevation over a long horizontal distance are represented by widely-spaced contour lines.
Valleys - these appear as a series of "V" shaped curves. The point of the and when there are streams in the valleys
"V" always points toward the head of the valley the "V" always points upstream .
Saddles - The space between 2 peaks can be recognized by its hourglass shaped contour lines.
Cliffs - since they represent dramatic changes in elevation over a short horizontal distance, cliffs are represented by
, closely-spaced contour lines.
Here are some examples of how terrain features are translated into contours, taken from a USMC training manual:
valley-along the
saddle (“crossing” the baseline between
cliff between 2 peaks) peaks (arrow shows
downhill water flow)
countour lines hourglass shape row of “v’s”
spaced close together

8-1 Science TOPOGRAPHIC MAPS - RULES OF CONTOUR LINES 4 th 6 Weeks
1. A contour line represents a single equal elevation: that is, all points on the same contour line have the same elevation.
2. Where one closed contour line surrounds another, the inner contour line represents the higher elevation.
3. The elevation represented by a contour line is always a simple multiple of the contour interval.
4. A contour line that closes within the limits of the map indicates a hill, ridge or plateau.
5. Commonly, every fifth contour line (index contour) is darker and its elevation is shown.
6. On the same map, closely spaced contour lines indicate a relatively steep slope, widely spaced contour lines indicate a relatively gentle slope, and uniformly spaced contour lines indicate a uniform slope.
7. Contour lines do not cross other contour lines. Exception: on a vertical cliff or a nearly vertical cliff, contour lines touch because they are on top of one another
8. Every contour line eventually closes against itself. However, the map area may not be large enough to show this closure. Therefore, the contours will end at the edge of the map.
9. Closed depressions are shown by hachured contour lines. The hachures point into the depression.
(Hachures = short dashes)
10. A hachured contour line, lying between two different contour lines, is the same elevation as the lower contour line.
11. Where two adjacent contours indicate opposite slopes (hachured contour next to plain contour), both are the SAME elevation.
12. Where a contour line crosses a stream or valley, the contour bends to form a “V” that points upstream or up the valley.

8-1 Science TOPOGRAPHIC MAPS 4 th 6 Weeks
_________________________, ___________________________ _____
(last name) (first) (per)
MATCHING – Each answer is used only once
1 ____
3 ____
5 ____
2 ____
4 ____
6 ____

8-1 Science TOPOGRAPHIC MAPS 4 th 6 Weeks
_________________________, ___________________________ _____
(last name) (first) (per)
This diagram represents a topographic map. Use it to answer the following questions:
1. ___ What is the elevation at the intersection of Jones Road and Smith Road?
A. 450 m B. 550 m C. 500 m D. 600 m
2. ___ What is the elevation of the highest contour line on hill W?
F. 440 m G. 560 m H. 510 m J. 610 m
3. ___ On which side of hill X is the steepest slope found?
A. north B. southeast C. east D. southwest
4. ___ In which general direction is Trout Brook flowing when it passes under Smith Road?
F. northeast G. southeast H. northwest J. southwest

8-1 Science TOPOGRAPHIC MAPS 4 th 6 Weeks
_________________________, ___________________________ _____
(last name) (first) (per)
Contour interval = 40 feet Units for elevation are meters (m) Map scale is 1cm = 0.4 km
1. (Round your answer off to one decimal place ) On the topographic map above, what is the actual distance on the earth's surface from point M to point N in kilometers? ______________________
What about from point E to point F in kilometers? ______________________
2. _____ The best estimate of the elevation of point B on the topographic map above is:
F 7,540 feet G 7,550 feet. H 7,560 feet. I 7,580 feet.
3. What is the elevation of the nearest contour line to each of these points:
D. _____________________E. _____________________ F. ______________________

8-1 Science Lab Exercise – Defining a Topographic Map 4 th 6 Weeks
Below is a sketch of a small mountain in the Appalachian chain near the east coast. A TOPOGRAPHIC map provides a way of looking at this hill on a flat map from an overhead view and be able to “see” how tall this mountain is and how it is shaped, without having to look at a picture of it or a diagram like this.
To see how a topographic map does this, you will construct your own topographic map of this mountain. When you’re done, you’ll give this mountain a name and turn it in for a lab grade.
Procedure
1 Mark the vertical lines that you see on either side of the mountain every 0.5 cm (every 5mm) with a small dash mark.
Label each mark in 50 meter increments. If you write too large to do this neatly, then simply number every centimeter
(every 2 marks) by 100 meters. It is not necessary to write the unit. Don’t forget to mark “0” (zero).
Remember “0” zero elevation is also called “sea level.” All elevations on any map are measured from sea level, no matter how far away the sea isl!
2 Use a ruler to draw lines of elevation across the mountain. Do this by connecting the pairs of dash marks on the number lines. Your lines should be written only on the mountains – NOT all the way across the page!
3 Next, line the edge of a sheet of graph paper along baseline (“0” meter line) of the mountain. Use your ruler to draw a long straight line from the end of each of your lines on the mountain to the bottom of the sheet of graph paper, or until you reach the end of your ruler (that would be far enough). illustration to see what this procedure looks like.
Use the graph paper lines to be sure your lines are perfectly vertical and not slanted (IMPORANT!) and draw these lines LIGHTLY (also important!). See the overhead
4 Now to draw the contour lines and make your map. Since we don’t know the shape of the sides of the mountain, we’ll use assume the mountain has an oval shape and use ovals for our “closed” ( connected ) contour lines.
5 Each pair of ends from one elevation line represent the anchor points of the contour line for that elevation. In other words, ALL POINTS ALONG THIS OVAL, all around the mountain, are at the same elevation (0m, 150m, 200m, etc). Start with the “zero” contour line and draw your largest oval. Then continue to connect the remaining pairs of lines with smaller and smaller ovals. See the overhead illustration to see what this procedure looks like.
Notice that the smaller ovals inside the larger ones are always at a higher elevation, just like a real
mountain gets smaller and smaller as you climb it. The exception are lakes and large holes or craters
– but they use special marks to show these.
6 When you have finally drawn the last (highest) contour line, label 0m, 100m, 200m, 300m, 400m contour lines and all others that are multiples of 100m. Please label each one twice, along the top of the oval and then on the other side of the mountain on the bottom of the oval.
7 Finally, place a small “x” inside the smallest oval to mark what you think is the absolute highest point of your mountain. This is the official way to show the “highest elevation” on a topographic map.
8 Write the correct heading on the top of your lab. Include the date, period, and your partners’ names.
9 Title your topographic map “TOPOGRAPHIC MAP of (make up a name for your mountain)” Staple your mountain diagram to the back of your graph paper before turning it in.