Agriculture Reference
In-Depth Information
The U.S. Geological Survey publishes maps at various scales. The
scale used for most U.S. topographic mapping is 1:24,000. USGS maps at
this scale cover an area measuring 7.5 minutes of latitude and 7.5 min-
utes of longitude, and are commonly called 7.5-minute quadrangle maps.
Map coverage for most of the United States has been completed at this
scale, except for Puerto Rico, which is mapped at 1:20,000 and 1:30,000,
and for a few states that have been mapped at 1:25,000. Most of Alaska
has been mapped at 1:63,360, with some populated areas also mapped
at 1:24,000. For countries where the metric system is used, map scales
follow the same proportional system, whereby 1:10,000 means one unit,
(such as one centimeter) equals 10,000 units (e.g., centimeters), or one
meter equals 10,000 meters. With practice and a degree of curiosity one
can quickly become conversant with such maps and effective at using
maps of all types for a variety of professional purposes.
