EAS 2200 Earth Systems
Lab Sessions (1146 Snee Hall)
TA: Chen Chen
Office: 4144 Snee Hall
Email: cc839@cornell.edu
Lab: Tu, Wed, 2PM - 4:25PM
Office Hour: Thursday, 3PM – 5PM
• Textbook: Lab notebook (bring it every week)
• Website:
http://www.geo.cornell.edu/eas/education/course/descr/EAS220/
• Lab Schedule: 12 indoor labs and 2 field trips
• Due Friday at 3PM: Mailbox on second floor
or my office
• No Late Labs!
• Topographic Map:
2-D representation of 3-D of Earth’s surface
Contour lines show elevation
eg: Fig 1 (next slide), Figure 7-B (Lab notebook)
GEOS - the pearson custom library for geography & geology
Fig. 1 Example of Topographic Map [1]
Rules for Contour lines
• Index Contours
• Contour Intervals
• How to draw contour lines:
a. have points: line the points on the same elevation
b. have contour lines: interpolation;
extrapolation
• Streams; Overhanging Cliff; Vertical Cliff;
Depression Contours; Steepness
GEOS - the pearson custom library for geography & geology
Fig. 2 Index Contour; Contour Interval [2]
Streams:
V pattern;
Apex of V points
upstream (uphill)
3 Streams on topographic map [3]
GEOS - the pearson custom library for geography & Fig.
geology
Contour Lines never
cross each other
except: where the
overhanging cliff is
present
Fig.4 Overhanging Cliff [4]
GEOS - the pearson custom library for geography & geology
Contour lines
merge to form a
single contour
line
Fig. 5 Vertical Cliff [5]
GEOS - the pearson custom library for geography & geology
Depression
contours: hatchure
on the downhill
side represent
closed depressions
Steepness:
Steep slope: close
contour lines;
Gentle slope: far
apart contour lines
Fig. 6 Depression Contours [6]
GEOS - the pearson custom library for geography & geology
Other Stuff for Reading Map
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Relief: elevation difference between 2 points
Gradient: Relief / Distance between 2 points
Valley: High elevation on both sides
Ridge: High elevation in the middle
Top of the hill: contour lines repeat on
opposite sides of a depression
• Side of the hill: only repeat on one side
GEOS - the pearson custom library for geography & geology
When it comes to complicated maps…
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Latitude and Longitude
Map Legend
Scales
PLS (Public Land Survey System)
GPS (Global Positioning System
UTM (Universal Transverse Mercator System)
GEOS - the pearson custom library for geography & geology
Complicated maps cont’
• Ithaca’s Location: 42°26’36”N, 76°30’0”W
• Latitude: 0 degree at equator; 90 N & S at
poles
• Longitude: east or west of Prime Meridian
(which runs through Greenwich, England)
• Quadrangle: section of Earth’s surface
bounded by latitude and longitude
GEOS - the pearson custom library for geography & geology
Complicated maps cont’
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Scales:
1: 24,000: Ratio Scale
1/24,000: Fractional Scale
One inch on the map equals one mile on the
ground: Verbal Scale
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Bar Scale:
GEOS - the pearson custom library for geography & geology
Complicated maps cont’
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PLS: (United States) Public Land Survey System
Principal Meridians: N – S lines
Base Lines: E – W lines
Township (T1N, T2N) and Range (R1W, R2W)
Township (6 * 6 miles)  36 Section
Section  NW ¼, NE ¼, SW ¼, SE ¼. And can be
further divided
• Go from SMALLEST to BIGGEST when write this
up
GEOS - the pearson custom library for geography & geology
W
What is located in the SW1/4, SW1/4, sec. 14, T2S, R3W?
Complicated maps cont’
• GPS: Use Satellites to define position on the
Earth relative to the World Geodetic System –
based on UTM
• UTM (Universal Transverse Mercator System):
60 N – S zones. (the surface of Earth between 80°S
and 84°N latitude)
• Specify a position: Easting coordinates,
distance from W to E, in meters
Northing coordinates,
distance from equator (10,000,000 meters)
GEOS - the pearson custom library for geography & geology
Topographic Profile and Vertical
Exaggeration
• Topographic Profile: cross section
• Mark the section line with elevation
information
• Write down marks on a sheet of paper; two
ends; streams
• Calculate vertical exaggeration:
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(I prefer this one…)
vertical ( fractional )
horizontal ( fractional )
GEOS - the pearson custom library for geography & geology
References
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www.town.ithaca.ny.us/trans/facts/maps/3%20Topographic%20Map.pdf
http://www.athro.com/geo/topo/image_f_stream.jpeg
http://ozultimate.com/bushwalking/walk/722/125_2582.jpg
http://dogonlanguages.org/photos/057_07_vertical_fracture_in_cliff_Kikara_JH.JPG
http://www.iupui.edu/~geogdept/g108/cont_3.gif