Measuring the World
Why Elevation Follows Gravity: The Geoid Beneath Every Height
GNSS measures height above a mathematical ellipsoid, but practical elevation depends on gravity, the geoid, and a physical definition of level.
From the Index
Tag: Geoid Models
The gravity-based models that help connect satellite heights with physical elevation.
Measuring the World
The New NSRS Is Coming: A Field-to-Office Guide for Surveyors
An entry-level, field-to-office guide to NATRF2022, NAPGD2022, SPCS2022, epochs, height modernization, and preparing survey workflows for the modernized National Spatial Reference System.
Measuring the World
Surveying the Highest Peak, Part 3: GPS, Geoids, Snow, and the Modern Height of Everest
Why modern Everest measurements depend on GNSS, gravity, snow depth, reference frames, and a clear definition of height.
Measuring the World
Finding Level: From Water Levels and Spirit Bubbles to Digital Heights
Establishing height has always required a definition of level, a reliable sight line, and a path of observations strong enough to reveal accumulated error.