Scale Order of Magnitude Index
Index LEVEL SCALE EXAMPLE National Map
Accuracy
Standard
6 International 1 : 106 1 : 2 000 000 1 mile +/-
5 Federal 1 : 105 1" = 20,000' 500' +/-
4 State 1 : 104 1" = 2,000' 50' +/-
3 County 1 : 103 1" = 200' 5' +/-
2 Municipal 1 : 102 1" = 20' 6 inches +/-
1 Facility 1 : 101 3/8" = 1' - 0" -
0 Object 1 : 100 half scale -


The National Map Accuracy Standard (NMAS) generally requires map products to be produced with an accuracy within 1/40 of the map scale.
"Large scale" mapping includes scale index 2 and 3, while "small scale" mapping includes scale index 4, 5 and 6.



The SOOM Index is in the public domain. The SOOM Index was first published as a government document for the State of Ohio. The citation reads:

Hansen, Soren Survey of Users of Geographic Information Management Systems
OGRIP (Ohio Geographically Referenced Information Program), Columbus, OH, August [1993] - page 33.

The report may still be available at the OGRIP web page


The reference URL ID for this page is www.en.com/users/soren/SOOM.htm