EART 109
Field Geology
Spring 2010
NAME_________________________
LAB 2
Campus Topo Exercise
During this exercise we will hike around the UCSC campus,
enjoying fresh air and sunshine while attempting to locate our
positions on two topographic maps: a campus map and the USGS 7.5’
quadrangle map. You will be asked to plot your precise location
at eight spots on both maps. Plot locations as accuracy and
precisely as possible. Following the walk, you will have the
opportunity to practice measuring strike and dip on plywood
boards (which are planes) at a site near the Earth & Marine
building. Completely answer all questions. If you go onto the
back of the page, clearly label which question you are answering.
Goals:
 Become comfortable with and proficient at using topographic
maps to locate yourself in the field.
 To learn to take bearings with your compass
 To learn to measure strike and dip on plywood boards with a
Brunton Compass
 To plot bearings on a map while in the field.
 To understand the effects of scale on the use of topographic
maps
 To assess the use of GPS data in the field.
1. Fill in the table below.
Verbal Scale
Contour
Interval
Fractional
Scale (ratio)
Campus
Topographic Map
Santa Cruz 7.5’
Quadrangle
2. As you hike around campus, keep track of your progress on
the topographic map. At each stop, plot your location on
both maps and record your GPS location and elevation.
Use topographic inspection to locate yourself – don’t use
the GPS position when plotting on your map. You will
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compare the two methods later. Verify your location by
shooting bearings and cultural features. Plot bearings on
your campus and Santa Cruz quadrangle maps. Use pencil.
Watch out for poison oak.
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GPS DATA POINTS
Latitude
Longitude
Elevation
Dip
Dip Direction
Location 1
Location 2
Location 3
Location 4
Location 5
Location 6
Location 7
Location 8
MEASUREMENTS OF ATTITUDE OF PLANES
Strike
Plane 1
Plane 2
Plane 3
Plane 4
Plane 5
Plane 6
Plane 7
Plane 8
Post-Walk questions:
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3. Comment on the effect of map scale on your ability to locate
positions accurately.
4. At some of the sites, you have shot bearings to landmarks to
establish your position on the map. Discuss the effect of
the angle of intersection between two or more bearings on
the accuracy of your location. Draw a sketch that
illustrates this effect.
5. How does the distance to a site being used for triangulation
affect the accuracy of finding your location?
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6. On the campus map, how many inches equals 25 feet on the
ground? (Show your work)
7. On the USGS 7.5’ Quadrangle map, how many inches equals 70
feet on the ground? (Show your work)
8. (SHORT ESSAY) Discuss the relative benefits and shortcomings
of using the GPS to locate yourself. How much do local
conditions at a particular site determine the relative
utility of GPS vs. topographic inspection or shooting
bearings?
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