Topographic Maps by dfhdhdhdhjr

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									Topographic Maps
Wednesday, January 25, 2012
What is a topographic map?
 A map that
 shows
 elevation
 changes for
 a specific
 region.
 PURPOSE OF A TOPO MAP
  A MAP PROVIDES INFORMATION ON THE
EXSISTENCE OF, THE LOCATION OF, AND THE
 DISTANCES BETWEEN GROUND FEATURES.
             Contour Lines

Contour lines indicate elevation. They are the
main part of any topographic map.
Regular Contour Lines
Regular
contour
lines are
normally
the thin
brown
lines
which
dominate a
topo map.
Index Contour Lines
 Are thicker and are
 labeled with an
 elevation.
Read Between the Lines!
 The closer the lines
 are, the steeper the
 slope. The further, the
 more gentle
Gradient
Contour
 Each of these kids
 stands upon a different
 contour line. Yes, it’s
 imaginary.
Get the Idea?
 With a regular map, we can get the outline of the
 island, but have no idea as to elevation change
 (topography).
All Elevation Below 10
Feet Under Water
 Notice how the island has shrank a bit.
All Below 20’ Under!
All Below 30’ Under!
That’s The Idea!
Can You Guess The Elevation?
Contour Interval
 Amount of
 elevation
 change between
 each contour
 line.
What is the Contour Interval?
Streams
Closer Look: Streams
Plateaus (Summits)
Note: Index, Depression
Note: Pond/Lake
Various Roads/Highways
HILL: AN AREA OF HIGH GROUND. FROM
A HILLTOP, THE GROUND SLOPE DOWN IN
ALL DIRECTIONS.
VALLEY: A STRETCHED-OUT GROOVE IN
THE LAND, USUALLY FORMED BY
STREAMS OR RIVERS.
RIDGE: A SLOPING LINE OF HIGH GROUND.
SADDLE: A DIP OR LOW POINT BETWEEN
TWO AREAS OF HIGHER GROUND.
DEPRESSION: A LOW PO INT IN THE GROUND
OR SINKHOLE. THEY ARE REPRESENTED BY CLOSE
CONTOUR LINES THAT HAVE TICK MARKS POINTING
TOWARD LOW GROUND.
DRAW: A LESS DEVELOPED STEAM COURSE THAN A VALLEY.
THERE IS ESSENTIALLY NO LEVEL GROUND AND, THEREFORE,
LITTLE OR NO MANEUVER ROOM WITHIN ITS CONFINES.


         )
SPUR: A SHORT, CONTINUOUS SLOPING LINE OF
HIGHER GROUND, NORMALLY JUTTING OUT FROM
THE SIDE OF A RIDGE.


      FM 21-26: PAGE 10-12 (FIGURE 10-23)
CLIFF: A VERTICAL OR NEAR VERTICAL FEATURE; IT IS AN ABRUPT
CHANGE OF THE LAND. THE SLOPE IS SO STEEP THAT THE
CONTOUR LINES CONVERGE INTO ONE CONTOUR LINE OR THE LAST
CONTOUR LINE HAS TICK MARKS POINTING TO LOW GROUND.
CUT: A MAN-MADE FEATURE RESULTIING FROM CUTTING
THROUGH RAISED GROUND, USUALLY TO FROM A LEVEL BED
FOR A ROAD OR RAILROAD TRACK.

FILL: A MAN-MADE FEATURE RESULTING FROM FILLING A LOW
AREA, USUALLY TO FORM A LEVEL BED FOR A ROAD OR RAIL-
ROAD TRACK.

								
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