# What is topographic or contour map

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```					  What is a
topographic
(or contour)
map?
A topographic map shows elevation –
or how high or low a land feature is.
   It shows features such as –
 Mountains

 Hills

 Lakes

 Depressions  or valleys
 By using lines on a flat map.
A topographic
map is
sometimes called
a contour map.
Here are some examples
of topographic maps.
You can understand
how high or low a
geographic feature is
on a contour map
because of its use of
numbered lines.
 The lines are called CONTOUR LINES.
 They are a certain distance apart.

 The number of meters or feet in
between each contour line is called the
CONTOUR INTERVAL.
 For example – if a hill is shown as 10
feet, 20 feet, and thirty feet – the
CONTOUR INTERVAL is 10 feet
because that is the difference between
each contour line.
Not all contours lines go up!
 Sometimes, a land feature like a valley
or depression is found on a map.
 Instead of a regular contour line, the
feature will instead have a contour line
with little “hatchure” marks going down.
These marks look like little slashes.
 This tells us that instead of going up in
elevation, that particular land feature is
going down.
On the next slide, you’ll see a
contour map of excavations at the
old Twin Towers site in New York
City. Construction crews uncovered
glacial formations 20,000 years old
once they removed the soil. Instead
of using hatchure marks, the
cartographers used negative
numbers to show that all landforms
went into the ground rather than
above it.
A topographic map can
also show you what
the land is like. For
example, a swampy
area will be shown
with little sprigs that
look like plants.
How can you quickly find
steep hills and mountains?
 Just look for the shaded areas on the
map.
 The steeper a feature is, the closer
together the contour lines will be.
 In other words, the steepest areas
on a map are the ones that look the
darkest.
 Here is an example…
You will be starting a
map lab and will be
on contour maps.
Remember what you
just learned and you
will be able to “see” a
land feature in three
dimensions, even
though the map itself
is flat!
THE END

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 views: 19 posted: 12/9/2011 language: pages: 21