horizontal rule National Geologic Map Database logo
Help Information
Map Scale horizontal rule

Map scale can be expressed as the ratio or proportion between a distance on a map and the actual distance on the land surface. This ratio is called the Representative Fraction (RF). A RF of 1:100,000 indicates that 1 unit of measure on the map represents 100,000 units on the land surface (i.e., 1 inch = 100,000 inches - 1.58 miles).

To search by MAP SCALE, you may specify:

  • one map scale (enter a value in the top box only)
  • a scale range such as 1:24,000 through 1:100,000
  • all maps at a scale, and more detailed (enter a value in the bottom box only

For maps at exactly 1:24,000 scale:
Scale Range
Most detailed (or exact scale
1:
 
Least detailed (or leave blank)
1:
 
For maps at 1:100,000 and larger scale:
(e.g. 1:100,000 1:50,000 1:24,000 etc)
Scale Range
Most detailed (exact scale)
1:
 
Least detailed (or leave blank)
1:
 

Leave this entry blank if you do not wish to limit your search by Map Scale.


The following information may be useful regarding map scales.

large scale map image medium scale map image small scale map image
More Detail <-------------- ---------------> Less Detail
Larger Scale Smaller Scale
1:24,000 1:100,000 1:500,000 1:1,000,000

horizontal rule