Measuring the World
A History of Datums in America, Part 2: NAD 83, HARN, NAVD 88, and the GPS Era
How NAD 83 evolved through the 1986 adjustment, 83/90-era networks, HARN, FBN, CORS96, NSRS2007, and NAD 83(2011)—and how NAVD 88 replaced NGVD 29.
From the Index
Tag: Geodetic Control
Reports, histories, and working notes filed under this subject.
Measuring the World
A History of Datums in America, Part 1: From Colonial Surveys to NAD 27 and NGVD 29
From colonial metes-and-bounds surveys and Mason and Dixon to the Coast Survey, U.S. Standard Datum, NAD 27, State Plane coordinates, and NGVD 29.
Engineering & Infrastructure
Surveying the Panama Canal, Part 2: Control, Excavation, Locks, and the Culebra Cut
The survey control, grades, quantities, alignment, and records behind the canal’s locks, dam, and massive excavation.
Engineering & Infrastructure
Before Liftoff: Surveying, Control, and Alignment at a Launch Complex
How construction control, structural monitoring, precision alignment, and verification support a rocket before it leaves the pad.
Exploration & Places
Surveying the Highest Peak, Part 1: Building the Great Trigonometrical Survey
How baselines, giant theodolites, triangulation, and an immense field organization carried a geodetic network across India.