EAS 2200 Earth SystemsLab Sessions (1146 Snee Hall)

TA: Chen ChenOffice: 4144 Snee Hall

Email: cc839@cornell.eduLab: 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)

Fig. 3 Streams on topographic map [3]GEOS - the pearson custom library for geography & 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

Fig. 5 Vertical Cliff [5]

Contour lines merge to form a single contour line

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

• 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…

• 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’

• Scales: • 1: 24,000: Ratio Scale• 1/24,000: Fractional Scale• One inch on the map equals one mile on the

ground: Verbal Scale• Bar Scale:

GEOS - the pearson custom library for geography & geology

Complicated maps cont’

• 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: • (I prefer this one…)

€

vertical( fractional)horizontal( fractional)

GEOS - the pearson custom library for geography & geology

References• 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