Physical Geology 101 Laboratory
Topographic Map Lab II
Introduction & Purpose:
Topographic maps are much scaled down
two-dimensional paper models of the Earth’s three-dimensional land
surface. The characteristic that makes
topographic maps unique are contour lines, which are map symbols that express
surface relief – ground elevation changes across a given tract of land. Each contour line represents a continuous set
of surface point locations that have equal elevation. The topographic (“topo”
for short) map is an ingenious invention that helps humans navigate across the
Earth’s surface, and analyze the Earth’s surface morphology, and geology.
Learning how to create and read topographic
maps can be difficult, especially for those people who are not graphically
and/or three-dimensionally minded.
However, if the basic concepts of contour lines, map scale, and
coordinate positioning systems are properly understood, then
the ability to read topographic maps will come much easier. The
purpose of this lab is to learn how to read, interpret, utilize, and create
topographic maps and topographic map profiles.
The major objectives of this laboratory
exercise are as follows:
a) Be able to interpret all the necessary map
information, including map scale, declination, contour interval, map symbols,
and map coordinates.
b) Be able to locate and identify features on a map,
including the use of map coordinates, identifying geographic features, and
reading and assigning compass bearings.
c) Be able to construct a simple topographic profile.
d) Be able to use a compass for orienteering purposes.
Instructions: Complete the following map analysis activities for the Yosemite
Topographic Map
supplied by
your instructor.
Section A: Topographic Fundamentals and Features
Map Origin Information
1. What’s the name of this map? ______________________________________
2. What year was this map first published? _________
3. What organization created this
map?
______________________________________
4. How was topographic contouring of
this map generated?
_______________________
5. What type of map projection was used to create this
map? ________________________
Map Scale
6. What is the ratio scale of this map? _______________
7. What is the verbal scale of
map? One inch of map distance equals ______ inches
of
real
ground distance.
8. Roughly how many square miles of real ground does this
map cover? ______________
Magnetic Declination
9. What is magnitude and direction
of the magnetic declination? ___________
10. Name the topographic map that
continues to the NE of this map?
_________________
Map Features and Symbols
11. What’s the difference between the solid green pattern and small dotted green pattern on
this map?
_______________________________________________________________
12. What’s
the difference between black dashed single lines and black dashed double lines?
______________________________________________________________________
13. What’s the difference between black
dashed double lines and black solid double lines?
______________________________________________________________________
14. What type of symbols represents
buildings on the map? ________________________
Map Coordinate Systems
15.
What are the black longitude and latitude tick mark intervals along the edge of
map? _____
16. Which UTM zone is this map area
located in? ______
17. What are the blue UTM tick mark
intervals along the edge of the map?
____ meters apart
Establishing Location
18.
What are the longitude
and latitude for each of these two
opposite corners of this map?
NW Corner SE
Corner
Longitude: ______________ ______________
Latitude: ______________ _____________
19.
What are the UTM
coordinates for each of the two
opposite corners of this map?
NW Corner SE
Corner
Easting: ______________ ______________
Northing:
______________
______________
20. Interpolate the best
approximate longitude and latitude for these locations:
Half Dome
Longitude: _______________________ ________________________
Latitude: _______________________ _________________________
21. Interpolate the best approximate longitude and latitude for these
locations:
Clouds Rest
Mt Star King
Easting: _______________________ ________________________
Northing:
_______________________
_________________________
Establishing Bearing and Distance
22. Calculate the bearing
and distance from Half Dome to Clouds Rest.
Quadrant bearing: _________________
Azimuth bearing: _________________
Distance (miles): _________________
23. Calculate the bearing and distance from Glacier Point
to
Quadrant bearing: _________________
Azimuth bearing: _________________
Distance (miles): ________________
Elevation Contours
24. What is the contour interval of the map? ______________
25. What is the contour interval between the
dark/thicker contour lines?
_____________
26. What is the
base level datum (“zero” elevation used to establish all contour and point elevations on
this map? ___________________________________
27.
What is the highest measured elevation
(benchmark) on this map? ________________
28.
What is the lowest measured elevation (benchmark) on this map?
_________________
29.
What is the total relief of this area?
__________________
Contours Patterns
30. Very
tightly-spaced contour lines represent what type of geographic features?
Answer:___________________________
31. Very
broadly-spaced contour lines represent what type of geographic features?
Answer:___________________________
32. Sets
of contour lines that form “V”-shaped patterns pointing to lower elevations
represent what sort of general geographic feature? (hint:
either stream valleys or ridge lines)
Answer:___________________________
33. Sets of contour lines that form “V”-shaped patterns
that point to higher elevations
represent what sort of geographic feature? (hint: either stream valleys or
ridge lines)
Answer:___________________________
Geographic Features
34. Which
direction does the Merced River Flow through
Answer:
_________________________________________________________________
35. What special name is used in
Directions: Follow the steps on
page 187 to create a topographic profile (see Figure 9.22). Note
that the
vertical exaggeration of a topographic profile is defined as the difference
between the
vertical
(elevation) scale and the horizontal (lateral ground distance) scale.
36. Construction of the Tanaya Creek Profile A-A’
Instructions: Construct a
topographic profile of the eastern end of
Tanaya Creek
from the top of Mt. Watkins (A) to the top of Clouds Rest (A’).
a. Review
the instructions for creating profiles in your lab manual (Part 9B 0pg. 189)
b. Use only the dark/bold contour lines
c. Do not vertically exaggerate (your vertical scale is
the same as your horizontal)
37. Construction of the
Instructions: Construct a topographic profile of the central
portion of
The
Rocks (B’). Review points a-b-c above used for Tanaya Creek profile.
38.
Comparison between the Tanaya Creek and the
Describe the general shape of each of the
profiles across
Tanaya
Creek Profile A-A’ - _________________________________________
39.
Compare the two profiles described above in terms of “V” shaped versus
“U” shaped.
Explain which type of erosional
agent you think is primarily responsible for the shaping of
each of these two
sections of
ice (glaciers).
Briefly explain your choice. Hint:
Check the back of the map for info.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Part III. Topographic Map
Laboratory Reflection
Directions: Write a reflection (minimum 100 words in
length) about your experience in doing the topo map
exercises lab today. Include the
following: 1) What was the purpose of the lab?; 2)
What did you actually learn from this laboratory?; 3) What did you find
interesting? 4) What were the problems and challenges you encountered; and 5)
what’s your opinion on how this lab was designed and executed.