“A ratio which compares a measurement on a
map to the actual distance between locations identified on the map.”
A topographic (topo) map’s scale
information is located at the bottom center of the map. Other maps will generally have scale
information in the large map key that outlines many of the features and data
printed on the map.
The map scale for a United States
Geologic Survey (USGS) 7.5 topo minute map is highlighted below.
A closer look of the scale
information:
1inch
: 24,000 inches
There are many other maps
produced by government agencies (federal and state), parks and private
companies. There are also many scale
options to be found too. Some maps will
use similar ratios such as 1:250,000 while others will simply state: 1inch = 2 miles. Here is another example; below.
The bar scales (see above) provide the best visual
representation of scale. The bar scales
provide data in miles, kilometers, nautical miles or feet. Notice the small graduations to the left of each
scale. In the case of the kilometer
scale, the graduations are in units of 1000 meters. This gives you the detail for measuring
distance on a map.
To complete the navigation picture I always refer a second
map, such as a map of the national forest (e.g., the Deschutes National
Forest.) Commonly, such a map will be
“zoomed” way out and have a scale of 1:100,000 or 1:250,000. Imagine that such a map would be made up of
many 7.5 minute quadrangles.
Other options are available to the hiker. For example DeLorme produces an atlas and
gazetteer for every state; visit delorme.com. National Geographic has excellent
1:24,000 scale maps for many of the national parks. My most recent map came on waterproof paper
and was very up to date. My favorite
product is made by mytopo.com and is the mapping software Terrain
Navigator. I’ve been using this software
in its various releases since 1998.
Terrain Navigator allows the hiker to up load/down load waypoints and
tracks from many GPS receivers, has tools for backcountry planning, provides
several map scale and zoom options and is very simple to use.
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