First lets recognize that map symbols are color
coded. Symbols in green indicate vegetation, symbols in blue
represent water, brown is used for topographic symbols, man made features
are shown in black or red. Lets look at the symbols labeled in the
Contour lines are lines that indicate elevation.
These are the lines that show the topography on the map. They are
discussed in more detail in the next section. Contour lines are
shown in brown. Two types of contour lines are shown.
Regular contour lines are the thinner brown lines, index contour lines
are the thicker brown lines. The numbers written in brown along
the contour lines indicate elevation of the line. For this map
elevation is in feet above sea level.
Forests and Clearings
Forested areas are represented by areas shaded green;
for Spruce Knob this means most of the area. Areas that are not
forested are left unshaded (white). Note that not all topographic
maps show forests. Also note that this information is not always
up to date or accurate. I have struggled to walk across densely
wooded areas in places that have been mapped as "clearings".
Streams and other water features are shown in
Roads and Trails
Man made features are shown in black or red.
Trails are represented as thin single dashed lines. Roads are
represented as double lines or thicker red lines. A series of
symbols are used for roads to indicate the road quality; from double dashed lines
for dirt roads to thick red lines for major highways. In the case
of the Spruce Knob area we have two types of road, the thin double black
lines and the thin dashed double lines.
Like other man made features buildings are shown in
black. Solid squares usually indicate buildings that would be
inhabited by people (i.e. a house), hollow shapes usually indicate
uninhabited buildings (for example, a barn) (Note this may not hold for
maps in the future because it is not possible to determine what a
building is used for from the aerial photos used to make the
maps). Other man made features shown in black on our example
include the lookout tower on at the summit of Spruce Knob and the radio
tower. Though not seen on our map, larger buildings, such as
factories, are shown by larger shapes that outline the shape of the
building, and cities with closely spaced houses are shaded pink instead
of showing individual houses.
Even though these are not physical features you can see
on the ground, boundaries are shown on topographic maps by black or red
lines. Boundaries are usually represented by broken lines (combinations
of dots and dashes of different sizes). Different patterns are
used for different types of boundaries (i.e., state, county, city,
etc). On our example the boundary that is shown marks the edge of
a National Forest.
Bench marks indicate places where the elevation has
actually been surveyed. These locations are indicated on the map
by a triangle if a marker has been placed in the ground (see photo on
right), or an "x" if
no marker was left behind. Near either symbol are the letters
"BM" and a number which represents the elevation of that particular
location. Bench marks are shown in black on topographic