Louisiana Administrative Code
Title 43 - NATURAL RESOURCES
Part XXVII - State Lands
Subpart 1 - Land Information Mapping and Map Records System
Chapter 11 - Aerial Triangulation
Section XXVII-1103 - Coordinate Object Space

A. Aerial triangulation shall be performed in a Local Space Rectangular System based on the Geodetic Reference System 1980 (GRS 80) ellipsoid. Geoid separation from the ellipsoid shall be established for each project area and referenced to NAD 83 for photogrammetric purposes. The Local Space Rectangular System shall be configured as secant at its origin and shall have a negative ellipsoid height at origin as established for the specific project area.

B. Elevations shall be referenced to the National Geodetic Vertical Datum of 1929, or subsequent NAVD 88 datum, as applicable, and shall be assumed to be in perfect coincidence with the ellipsoid surface (no geoid slope). The input and output coordinate systems shall be in geodetic coordinates (NAD 83) of Latitude, Longitude and Orthometric Height to ensure proper utilization of the Local Space Rectangular (LSR) System for the aerial triangulation computational solution. Separate transformations shall then be performed on the triangulated positions to index elevations back to NGVD 1929 or NAVD 88 datum and to express horizontal coordinates in the Louisiana State Plane Coordinate System, NAD 83, North or South Zone, as applicable.

C. For each aerial triangulation block solution performed, the contractor shall take extraordinary care to record and preserve the LSR system origin used for the solution. Variance-covariance matrices should be referenced to the LSR system for both camera stations and triangulated ground points if supplied with the aerial triangulation report. However, an error propagation of the bundle adjustment will not be required. The responsible contracting authority may perform an error analysis independently to validate the contractor's work.