I' Contour MapsIntroduction

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I. Contour Maps--Introduction

• 20 September 2007

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RELIEF difference in elevation between two
points.
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• Why are there
• two roads from
• Louberg to
• Luluville?
• .

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• Dingle Rd. goes
• around the Mts.
• while Bo Ring Way
• goes UP OVER the
• the Mts.

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CONTOUR LINE connects points of EQUAL elevation
(BROWN LINE)

• A map with
• topographic
• contours.

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CONTOUR INTERVAL distance in elevation between
consecutive contour lines

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The island from above.
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II. Labeling Contours
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• Island with its
• CONTOUR
• LINES.

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• Looking down
• from above.

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• Contour Interval
• (C.I.)250 feet.
• --Labeling EVERY
• line with an
• elevation gets
• too cluttered.

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Instead, we use an INDEX INTERVAL every FIFTH
line is labeled and thicker.
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BENCHMARK an exact point of elevation that can
be marked with an X, , or BM.
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Notice any place INSIDE a contour line is
HIGHER than the contour line. Any place OUTSIDE
a contour line is LOWER than the contour line.
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III. The V Rule
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Contour lines bend to form a V when they cross a
river. The V points upstream. Therefore, the
river flows the other way.
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NOTES ARE FINISHED FOR TODAY (20 Sept. 2007)

• Work on assignment until the bell.

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IV. Depression ContoursGetting into and out of
a hole.

• 20 September 2006

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The highest point (1397) is on the rim between
its outer slopes and crater.

• C.I.200

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Contours betw. 517 and 1397 are fine. But, you
cannot have a 1200 line INSIDE a 1200 line, and
1000 line INSIDE a 1200 line.

• Everything inside
• a contour is
• supposed to be
• HIGHER than the
• contour.

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DEPRESSION CONTOUR indicated with teeth called
HACHURES.

• Hachured contours
• a point inside a
• contour is lower
• than the contour.
• --A point outside a
• contour is higher
• than the contour.

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From the rim, the land goes down on BOTH
sidestowards the outside of the volcano and
inside the crater.
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V. Contour Spacing and Steepness
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NOTICE the slope from atop Mt. Tipster is much
STEEPER down to sea than the slope from atop Mt.
Riddle down to sea.
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NOTICE where the slopes are STEEPER the contour
lines are CLOSER. Where the slopes are GENTLER
the contour lines are FURTHER APART.
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What happens if you have a VERTICAL
cliff?????!!!!!!!
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With a cliff, the contours will come together and
merge. THIS IS THE ONLY TIME CONTOURS TOUCH!
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THE END

• Work on assignment for remainder of class.
• 20 September 2006

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