La. Admin. Code tit. 43 § XXVII-309
Current through Register Vol. 50, No. 12, December 20, 2024
Section XXVII-309 - Vertical AccuracyA. The development of vertical data necessary for the establishment of contour lines, spot elevations or related vertical information is optional except as necessary to facilitate survey network adjustments, analytic aerial triangulation, and related phases of final map compilation.B. In the event that development of vertical data necessary for the establishment of contour lines, spot elevations or related vertical information is required for inclusion on final topographic map products, the final map accuracy shall be such that 90 percent of the elevations determined from solid-line contours shall have an accuracy with respect to true ground elevation of one half the contour interval or better, and the remaining 10 percent shall not be in error by more than one contour interval. A contour which can be brought within the stated vertical tolerance by shifting its horizontal location by not more than one fortieth of an inch (0.025") will be considered acceptable. Solid line contour accuracies for various representative contour intervals developed under these standards are tabulated below. Contour Line Accuracy Requirements |
Contour Interval | 90% of Contours Within | Remaining 10% of Contours Within |
1' | +0.5' | +1.0' |
2' | +1.0' | +2.0' |
5' | +2.5' | +5.0' |
10' | +5.0' | +10.0' |
1. In densely wooded areas where heavy tree or brush cover fully obscures the ground and the contours are shown as dashed lines, 90 percent of the elevations determined from dashed-line contours shall have an accuracy with respect to true ground elevation of one contour interval or one fourth the average height of the ground cover, whichever is greater.C. At least 90 percent of all spot elevations shown on the final map shall be accurate within one fourth of the contour interval, and the remaining 10 percent shall be accurate to within one half the contour interval. Required spot elevation accuracies for various representative contour intervals developed under these standards are tabulated below. Spot Elevation Accuracy Requirements |
Contour Interval | 90% of Spot Elevations Within | Remaining 10% of Spot Elevations Within |
1' | +0.25' | +0.50' |
2' | +0.50' | +1.00' |
5' | +1.25' | +2.50' |
10' | +2.50' | +5.00' |
D. Ninety percent of auxiliary heights determined for buildings, trees, houses and related objects shall have an accuracy with respect to true ground elevation of two times the contour interval or better, and the remaining 10 percent shall not be in error by more than four times the contour interval.La. Admin. Code tit. 43, § XXVII-309
Promulgated by the Office of the Governor, Division of Administration, State Land Office, LR 17:968 (October 1991).AUTHORITY NOTE: Promulgated in accordance with R.S. 50:171.