Colors and symbols add the detail unique to a
topographic map. These details may not
be found in gazetteers or travel guides.
Map detail includes important information about elevation, water,
structures, trails, ground cover and roads; and much more.
“The mapmaker has
been forced to use symbols to represent the natural and man-made features of
the earth’s surface. These symbols
resemble, as closely as possible, the actual features themselves as viewed from
above.”
U.S. Army Field
Manual FM 21-28 Map
Reading and Land Navigation, 1993
Topographic maps are rich in symbols. Specific to a location, symbols identify
features such as buildings, springs, bench marks, mines and bridges. The United States Geologic Survey’s (USGS)
guide Topographic Map Symbols is four
pages long and lists dozens of symbols.
To view the USGS’s complete listing go here.
The following graphics are a sampling from Topographic Map Symbols. The symbols below are those used for rivers,
lakes and canals. Note the different
colors used.
The graphic below illustrates symbols related
to buildings and other man-made features.
Note that the color of these symbols is
predominantly black.
Let’s highlight a few symbols that the
backcountry hiker will find helpful (the symbol will be listed to the left.)
Bench
Marks are survey monuments. Location and
elevation data is accurate. Bench Mark
will be represented by the letters BM and next to it will be printed the
elevation data; see map above. In the backcountry,
Bench Marks will have a brass/bronze plate at the location to identify the
mark and its position data. Please do
not tamper with a Bench Mark.
Useful
to the hiker are four wheel drive roads (4WD) and unimproved roads. These are commonly called jeep roads and may
be usable on foot, horseback or mountain bike.
Some of these roads may not be passable by vehicle.
Thin, powder-blue lines represent
streams. What looks like a dashed blue
line (right half) represents an intermittent stream; a flow that may disappear
in dry weather.
I
recommend spending some time browsing through Topographic Map Symbols and to become familiar with the symbols
listed. The web site www.landnavigation.org
provides a fine review of colors and symbols that are linked to photographs.
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