When transmission pipelines span multiple jurisdictions, they inevitably encounter differing county, state, and federal mapping guidelines. If pipeline centerlines are compiled indiscriminately into a master GIS file without strict Helmert transformations, the spatial data becomes lethal.
The Intersecting Datum Failure
In a documented alignment failure, an interstate pipeline corridor was drafted using local county GIS parcel data based in older NAD83 implementations. During construction layout, contractors utilized RTK GNSS locked to the modern WGS84 reference frame. The resultant 4-foot horizontal discrepancy meant the physical trench encroached into a neighboring high-voltage utility easement.
The Financial Fallout
The cost of halting pipeline construction, re-dredging the trench, legally renegotiating affected eminent domain acquisitions, and settling construction delay damages exceeded $45 Million USD. This highlights the absolute necessity of rigorous State Plane to WGS84 conversion auditing prior to breaking ground.