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This topographic map was produced by the United
States Geological Survey and illustrates the community
of Northeast, Maryland which is located along the
shoreline of Chesapeake Bay. Topographic maps show
elevations of the land's surface (in feet above sea
level) through the use of contour lines. The brown
lines on this map are contour lines. They trace points
of equal elevation across the map. For example the
brown line with the "30" label in the left
central portion of this map traces points that are
30 feet above sea level across the landscape.
Let's consider the position of the 30 foot contour
line with the shoreline of Chesapeake Bay. The elevation
of Chesapeake Bay is considered to be sea level, or
zero feet. Note that there are two brown lines between
the "30" line and the Bay's shoreline..
The brown line closest to the bay traces points that
are ten feet above sea level and the second brown
line traces points that are 20 feet above sea level.
With lots of practice, experienced users of topographic
maps can quickly "read" the landscape and
realize where moutains, ridges and valleys are located.
Topographic maps show many other important features
such as highways, streets, buildings, railroads, political
boundaries, certain land use types and much more.
This topographic map was obtained from MapCard,
an online service that provides subscribers access
to USGS topographic maps for all 50 states and aerial
photo coverage for most of the US.
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