Thursday 11-13-14
1. Update SN (Journal Check Next Week!)
2. Grade Rock Cycle Lab & Types of Rocks WS3. Topographic Map Notes4. Lake Lackawanna WS
Topographic MapsBy the end of class be able to Interpret a
topographic map
– Identify where the slope is steep or gentle
– The elevation of locations on the map
– Where hilltops, valleys, & rivers are
– Draw a profile of a topographic map
Topographic Maps
• Two dimensional model of the Earth’s surface (represents 3-D world)
Shows surface features of the earth including;• natural features like rivers, lakes and mountains
• manmade features like cities, roads, and bridges.
Topographic Maps• A Contour Line –
- connects points of EQUAL elevation.- show elevation - and shape of the land
Relief – difference between highest and lowest contour lines on map
• What is the relief of this map?30 mHighest = 30 m
-Lowest = 0 m
Topographic Maps
• Contour Interval –difference in elevation between each line.
MUST be equal value between any 2 lines.
600-500 =
# of lines between =
100/5 = Contour interval = 20 feet
520
540560
580
100
5
Topographic Maps
• Index Contour – Usually every 5th line is printed darker and has an elevation printed on it.
Rules for Contours2. Contours form closed loops (even if not
shown of the map.) • The innermost circle is the top of the hill.
Rules for Contours3. Contours bend upstream (uphill) when
crossing a stream, forming a “V” or “U” in the map
Rules for Contours
4. The maximum possible elevation for a hill is “1” less than what the next contour “should” be.
The highest possible elevation of the hill is just below the value of the next line that is not shown
5060
70
80
90
Depressions
• Contour lines which show a depression, crater, or sinkhole on a map.
• Shown by dashed lines (hachure marks) on the inside of a contour line
• The elevation of the first depression contour is the same as the lowest regular contour near it.
Rules for ContoursThe lowest possible elevation for a depression is “1” more than what the next contour “should” be.
The lowest possible elevation of a depression is just above the value of the next line that is not shown
50
90 90
80
7060
51
Benchmarks
• a location whose exact elevation is known and is noted on a brass or aluminum plate.
• bench marks are shown on maps by an X with the letters BM written next to them.
Gradient
• The slope between any two points on a hill
• Gradient = Change in Elevation
Horizontal Distance
Rise (Y)Run (X)
Gradient
200
Contour Interval = 20 ft
0 2 4 6 8 10
miles
220280
280 ft – 220 ft
60 ft5 mi
= 12 ft/mi
Change in elevation =
= 60 ft
Distance travelled = 5 mi
Change in Elevation
Horizontal Distance
1. Contour interval = 2. Relief =
3. Which hill has a depression at the top of it?
4. The highest mountain is
Color the steepest area red and the gentlest slope green
10m 40
Oak hill
Ash hill
• Fill out Planner for the week– Journal Check THURSDAY (or turn it in today for
extra credit!)• Check Trout Brook• Finish Notes• Topographic Map Lab• Start Review (front page only)
Monday 11-18-13