LAC 43:XXVII.307. Horizontal Accuracy

A. Ninety percent of all well defined planimetric features shall be plotted so that their positions on the final map and associated digital database shall be accurate to within one fortieth of an inch (0.025") of their true coordinate positions. None of the features shall be displaced on the final map and associated digital database by more than one twentieth of an inch (0.05") from their true position. These limits of accuracy shall apply in all cases to positions of well-defined points only. Well-defined points are points that are easily visible or recoverable from the aerial photography and are free from any overhead obstructions that may impair proper photo-interpretation. Examples of well defined points include property boundary monuments, intersections of roads and sidewalks, railroad intersections, corners of buildings or structures, manhole covers, power poles, and related features. B. Limiting horizontal positional errors for each respective map area classification and map scale ratio to be developed under these standards are tabulated below. Planimetric Coordinate Accuracy Requirements Ground (X or Y) for Well-Defined Points Area Classification | Scale Ratio | Planimetric (X or Y) Accuracy (Limiting Positional Error) Area Classification | Scale Ratio | 90% of Points at 1/40 Inch | Remaining 10% of Points at 1/20 of an Inch Class A | 1:600 | 1.3' | 2.5' Class B | 1:1,200 | 2.5' | 5.0' Class C | 1:2,400 | 5.0' | 10.0' Class D | 1:4,800 | 10.0' | 20.0' C. Multiple horizontal accuracies on the same map sheet to depict different contiguous area classifications are allowed provided that a diagram is included which clearly relates segments of the map with each respective area classification and associated accuracy.