FLOOD01751

• County: Fremont
• Community: Canon City
• Stream Name: Arkansas River
• Title: Canon City Community File
• Date: 1/1/2001
• Prepared For: CWCB
• Prepared By: CWCB
• Floodplain - Doc Type: Community File

UNITED STATES NATIONAL MAP ACCURACY STANDARDS

A. Horizontal accuracy. For maps on publication scales larger than
1 :20,000, not more than 10 percent of the points tested shall be in
error by more than 1/30 inch, measured on the publication scale;
for maps on publications scales of 1 :20,000 or smaller, 1/50 inch.
These limits of accuracy shall apply in all cases to positions of
well-defined points only. Well-defined points are those that are
easily visible or recoverable on the ground, such as the following:
monuments or markers, such as bench marks, property boundary
monuments; intersections of roads, railroads, etc.; corners of
large buildings or structures (or center points of small buildings);
etc. In general what is well-defined will also be determined by
what is plottable on the scale of the map within 1/100 i.nch. Thus
while the intersection of two road or property lines meeting at
right angles would come within a sensible interpretation, identi-
fication of the intersection of such lines meeting at an acute angle
would obviously not be practicable within 1/100 inch. Similarly,
features not identifiable upon the ground within close limits are
not to be considered as best points within the limits quoted, even
though their positions may be scaled closely upon the map. In this
class would come timber lines, soil boundaries, etc.

B. Vertical accuracy, as applied to contour maps on all publicati.on
scales, shall be such that not more than 10 percent of the elevations
tested shall be in error more than one-half the contour interval.
In checking elevations taken from the map, the apparent vertical
error may be decreased by assuming a horizontal displacement within
the permissible horizontal error for a map of that scale.

C. The accuracy of any map may be tested by comparing the positions
of points whose locations or elevations are shown upon it with cor-
responding positions as determined by surveys of a higher accuracy.
Tests shall be made by the producing agency, which shall also
determine which of its maps are to be tested, and the extent of such
testing.

D. Published maps meeting these accuracy requirements shall note this
fact on their legends, as follows: "This map complies with national
map accuracy standards."

E. Published maps whose errors exceed those aforestated shall omit from
their legends all mention of standard accuracy.

OFFICE OF THE STATE CARTOGRAPHEli
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