Louisiana Administrative Code › Title 43 - NATURAL RESOURCES › Part XXVII - State Lands › Subpart 1 - Land Information Mapping and Map Records System › Chapter 3 - Mapping Accuracy › Section XXVII-311 - Map Accuracy Test

Current through Register Vol. 50, No. 6, June 20, 2024
A. Testing for
				  horizontal accuracy compliance shall be performed by comparing the planimetric
				  (X and Y) coordinates of well-defined ground points to the coordinates of the
				  same points as determined by a horizontal check survey of higher accuracy. The
				  check survey shall be designed according to the Federal Geodetic Control
				  Committee (FGCC) 1984 Standards and Specifications for Geodetic Control
				  Networks to achieve standard deviations equal to or less than the one third of
				  the limiting positional error selected for the map. The distance between
				  control points used in the FGCC Standards for the design of the survey shall be
				  the horizontal ground distance across the diagonal dimension of the map
				  sheet.
B. Testing for vertical
				  accuracy compliance shall be performed by comparing the elevations (Z
				  coordinates) of well-defined points as determined from the map to corresponding
				  elevations determined by a survey of higher accuracy. For purposes of checking
				  elevations, the map position of the ground point may be shifted in any
				  direction by an amount equal to twice the limiting horizontal error in
				  position. The vertical check survey shall be designed according to FGCC
				  Standards to achieve errors in elevation differences at check point locations
				  no larger than one tenth of the contour interval. The distance between vertical
				  benchmarks used in the FGCC Standard for the design of the vertical check
				  survey shall be the horizontal ground distance across the diagonal of the map
				  sheet.
C. Discrepancies between the
				  X, Y or Z coordinates of ground points as determined from the map and by the
				  check survey that exceed the limiting error shall be considered unacceptable
				  and will be corrected before the map is considered to meet these standards. The
				  same survey datums, both horizontal and vertical, must be used for both the
				  project and the check control surveys.
D. At least three percent of the total area
				  mapped shall be selected at random and tested for compliance with these
				  standards. A minimum of 20 checkpoints shall be established throughout the area
				  covered by each map sheet selected. At least 20 percent of the checkpoints
				  shall be located in each quadrant of the map sheet and these points shall be
				  spaced at intervals equal to at least 10 percent of the map sheet
				  diagonal.
E. All maps produced
				  according to this accuracy standard shall include the following statement in
				  the title block:
"THIS MAP COMPLIES WITH NATIONAL MAP ACCURACY
					 STANDARDS."
F. Individual
				  map sheets checked and found to conform to this accuracy standard shall include
				  the following statement in the title block:
"THIS MAP WAS CHECKED AND FOUND TO CONFORM TO NATIONAL MAP
					 ACCURACY STANDARDS."
G.
				  When a published map is an enlargement of an original map manuscript or
				  associated digital database, that fact shall be stated in the legend. For
				  example:
"THIS MAP IS AN ENLARGEMENT OF A 1:1,200 ORIGINAL MAP
					 MANUSCRIPT."
AUTHORITY NOTE:
					 Promulgated in accordance with
					 R.S.
					 50:171.