Geology Reference
In-Depth Information
(use only alternate or heavy contour lines if they are
closely spaced).
This is done to bring out the topographic details in
areas of low relief. The vertical exaggeration is calcu-
lated by dividing the horizontal scale by the vertical
scale. Thus a profile with a horizontal scale of
1" = 2000'(1:24,000) and a vertical scale of 1" = 400'
(1:4800) would have a vertical exaggeration of five
times, that is 2000/400 = 5x (24,000/4800 = 5x).
Note that the units of measurement must be the same
for both the numerator (24,000) and denominator
(4800) to calculate a correct vertical exaggeration.
2.
Place the edge of the graph paper along the profile
line. Opposite each intersection of a contour line with
the profile line, place a short pencil mark on the graph
paper and indicate the elevation of the contour. Also
mark the intersections of all streams and depressions
and note, where appropriate, depressions or hills that
do not quite reach the next contour line.
3.
Project each marked elevation perpendicularly to the
horizontal line of the same elevation on the graph paper.
QUESTIONS 2, PART A
1.
Construction of a Contour Map.
The elevation of points
shown on the map in Figure 2.5 was determined by survey.
Abiding by the principles governing contour lines, you are
to draw in contour lines to make a topographic map. Use a
20-foot contour interval and assume that the land slopes uni-
formly between any two points of different elevation.
4.
Connect the points with smooth line and label
prominent features.
5.
State the vertical exaggeration. To avoid distortion,
profiles are drawn with equal vertical and horizontal
scales. However, it is usually necessary to use a verti-
cal scale several times larger than the horizontal scale.
