This document provides information about topographic maps, including: 1. Topographic maps show elevation, shape of the earth's surface using contour lines connecting points of equal elevation. Features like water, terrain, and human structures are shown through different colors and patterns. 2. Contour lines indicate elevation changes - closely spaced lines show steep slopes, widely spaced show gentle slopes. Contour lines never cross or branch. When crossing streams, they bend upstream. Closed contours indicate hills and depressions. 3. Topographic profiles show elevation changes along a line, often with vertical exaggeration to emphasize details. Gradient is the steepness of a slope. Constructing profiles involves connecting elevation points along a contour line slice

1. Earth ScienceEarth Science
Reading TopographicReading Topographic
MapsMaps

2. Definition of Topographic Maps
1. A graphical representation of the
three dimensional shape of the
earth’s surface that shows:
a) elevation
b) shape

4. Features of Topographic Maps
(not on notes page…)
TOPOGRAPHY (RELIEF):
- printed in brown
- contour lines shows hills, mountains, plains, etc.
WATER FEATURES:
- printed in blue
- includes oceans, lakes, ponds, rivers, canals, etc.
CULTURE:
- printed in black
- human-make works such as roads,
railroads, buildings, land boundaries, etc.

5. Features of Topographic Maps
Relationship between 3D and 2D representation
3D view
2D view

6. Key Terms:
Topography: general shape of the Earth.
Elevation: distance above sea level.
Contours: lines of equal value.
Contour line: is an imaginary line on the
surface of the earth connecting points of
equal elevation.

7. Contour lines
Relationship between topographic features and contour lines

8. Contour interval (C.I.) is the difference in elevation between any two
adjacent contour lines.
x
Relief: the difference between the highest and lowest elevation in a
particular area.

9. ADD to your notes page:
Contour index- extra dark line with numbers.

11. If we put contour lines on the island every
10 meters, it would look like this…

12. Now, let’s determine the elevation at
several points of the island…
0 – sea level
10 meters ~15 meters
+20 meters, but < 30
~8 meters

16. General Features of Contour Lines
Topographic Maps can show:
ELEVATION:
1.Contour lines connect
points of equal elevation.

17. Topographic Maps
can:
Show if the land is
STEEP or GENTLE:
2. Steep slopes are
shown by closely
spaced contour lines.
3. Gentle slopes are
shown by widely
spaced contour lines.
Contour lines do not
intersect, branch or
cross.

18. Topographic maps
can:
Identifying RIVERS
and STREAMS and
their FLOW:
4. When contour lines
cross streams they bend
upstream; that is, the
contour line forms a 'V'
with the apex at the
intersection with the
stream, and pointing in
an upstream direction.

19. Topographic maps show:
If there is a HILL or
DEPRESSION:
5. Closed contours
appearing on the map as
ellipses or circles represent
hills.
6. Closed contours with
hatchures, short lines
pointing toward the center
of the closure represent
closed depressions.

20. TOPOGRAPHIC MAPS: DEFINITIONS
Freebies:
#3 – gradient
#4D – profile
Bottom of page #7 – solid, intermitted
For numbers 1 – 4 (a – d)
Choose from these
words:
Contour line
Depressions
Elevation
Index
Interval
Topographic map
For numbers 1 - 8 at
the bottom, choose
from these words:
Gentle hill
hill
lowest
never
sea level
Steep hill
upstream

21. Answers:
1. Topographic map
2. elevation
3. Gradient
4. Contour line
a) Interval
b) Index
c) Depression
d) profile
1. Never
2. Hill
3. Steep
4. Gentle
5. Upstream
6. Sea level
7. Solid, intermitted
8. lowest

22. Write down:
Rules to determine the contour
interval (with multiple lines):
 Find the difference between the two
INDEX contours (a).
 Count contour lines between the
contour indexes, then add one (b).
 NOW DIVIDE (a/b)

23. A.
Contour
Interval?
B.
C.
D.
E.
The difference in
elevation between
the two index
contours (800 - 700)
is 100. We cross
five lines as we go
from the 700 line to
the 800 line (NOTE:
We count the lines
between the index
contours, then ADD
one. In this case,
we have 4 lines + 1
= 5). Therefore is
we divide the
elevation difference
(100) by the number
of lines (5) we will
get the contour
interval. In this
case it is 20.
720 m
740 m
760 m
780 m

24. 2. Determining a value of a depression…
 Determine the outer ring’s value.
 Outer ring is = to the lowest valued contour
line.
 In a depression – elevation DECREASES as
you go towards the center.
1. Determining a value of a hill…
 Determine the outer ring’s value.
 Outer ring is = nearest lowest valued contour
line PLUS contour interval.
 In a hill– elevation increases as you go
towards the center.

26. p
Row 1
10
30
10
30
20
0

27. Row 2
20
180
200
1400
5
+25

28. Row 3
100
1400
5
35
200
4400

29. Row 4
1
7
200
2400
100
400

30. Topographic Profiles
DEFINITIONS
- A topographic profile is a diagram that shows the
change in elevation of the land surface along any
given line (an area “looked from the side”).
- Gradient - The steepness of a slope as measured in
degrees, percentage, or as a distance ratio (rise/run).
- Change in elevation between 2 points/length of
measured 2 points. When dividing, make sure the
units are the SAME!!!

32. Vertical exaggeration (VE)
Topographic profiles are usually constructed with some amount of vertical
exaggeration (VE) to emphasize the details of topography.
The VE is determined by the following steps:
1 . Determine the number of feet represented by one inch on the vertical
axis of the topographic profile. In Figure 7-7C one inch represents 100 ft
or 1:1200.
2. The horizontal scale of the profile is the same as the map, 1:24,000.
3. The VE is calculated by dividing the horizontal scale by the vertical
scale.
VE = horizontal (map) scale/vertical scale
VE = 24,000/1200
VE = 20x
The VE of 20 indicates that the topography illustrated in Figure 7-7C is
exaggerated by 20 times that of the original map.

33. How to Make a Topographic Profile
This represents a very simple topographic map of a hill. The hill is steep on the left side (the
contour lines are very close together) and has a gentle slope on the right side. The numbers
represent the elevation of the contour lines. (*)
100
200
300
400
What would the hill look like if you were to slice it from left to right? (*)

34. 100
200
300
400
500 feet
400 feet
300 feet
200 feet
100 feet
Normally, the Earth’s surface is not this blocky. In a topographic profile a line is drawn from these
points (red dots) producing a smooth transition. (*)
Thus you have a topographic profile. This is what the hill would look like if you were to cut it
along the profile line and look at it from the side. (*)

36. Topographic Profile

37. Topographic Profile
Constructing a Topographic Profile

38. A B
6400
The contour interval of this map is 40 feet. Every index contour would then be 200 feet.
8000
7000
7600
7400
7200
7800
6800
6600

39. A B
6400
The contour interval of this map is 40 feet. Every index contour would then be 200 feet.
8000
7000
7600
7400
7200
7800
6800
6600
In this region the profile
line cut across the 7800
foot line 4 times. (*)
The last step is to simply connect the “dots”. (*)
The profile is finished. (*)

40. A B
6400
The contour interval of this map is 40 feet. Every index contour would then be 200 feet.
8000
7000
7600
7400
7200
7800
6800
6600
This is a very classic example of a butte with steep sides and a very flat top. The profile that you
see here is an exaggerated scale – the vertical scale is greater than the horizontal scale. The next
example is where the vertical scale is closer to the horizontal scale. (*)

41. THE GRAND CANYON, ARIZONA
This view of the Grand Canyon is from the South Rim looking north into Bright Angel Canyon.
This is what it looks like on a topographic map. (*)

42. THE GRAND CANYON, ARIZONA
This view of the Grand Canyon is from the South Rim looking north into Bright Angel Canyon.
This is what it looks like on a topographic map. (*)
It may not be as majestic but it is
full of information. (*)

43. Let’s take a look at this area from a topographic point of view. (*)

44. Cumberland, Pennsylvania/Maryland
This area is in the deeply eroded
folds of the Appalachian Mtns.
What type of drainage pattern is
shown in this area? (*)This a very good example of a TRELLIS PATTERN. The tributaries come in from the hills
and meet the main channel at almost 90o
. (*)
The tributaries are shown in blue and the main channel is shown in violet. What stage in
the cycle of stream erosion do these streams display? (*)

45. Cumberland, Pennsylvania/Maryland
Just for fun, let’s construct a topographic profile across
the main stream from point A to point B. (*)
AA
BB
Try to visualize what this
profile would look like
before you move on. (*)

46. Cumberland, Pennsylvania/Maryland
AA BB
Using every INDEX CONTOUR – 100 foot interval … (*)
1100
1000
900
800
700
600 Stream
Now just connect the dots and draw a smooth profile. The stream occupies the lowest
point of the valley. (*)