Washington Monument Even More Monumental

The Washington Monument is a bit taller than previously thought.

A team of government geodesists on Wednesday used satellites to take the monument’s most accurate measure ever. Their preliminary finding was that it’s 555 feet, 5.9 inches tall. Geodesy is the science of measuring the Earth.

Previously, the height of the monument has been reported as 555 feet, 5.5 inches. It was last measured 65 years ago by government surveyors.

Scaffolding erected for a renovation of the monument gave the team from the National Oceanic and Atmospheric Administration access to the top of the giant stone pillar.

The team from NOAA’s National Geodetic Survey took several measurements during its visit to the apex and will report final, detailed figures in about a week, NOAA officials said.

“You might think of this new technology as a satellite tape measure,” said NOAA administrator D. James Baker.

The geodesists used Global Positioning System receivers and other specialized gear to take hundreds of measurements at the top of the monument and at several other nearby Washington landmarks.

“Engineers will also use this information to monitor the monument’s stability, measuring any shifting, settling or other movement of the structure,” Baker said. He added that the same methods used in the project can be used for navigation, transportation and communication systems.

The last official geodetic measurements from the top of the Washington Monument were made in 1934 by the U.S. Coast and Geodetic Survey, the National Geodetic Survey’s predecessor agency. At that time, manual observations were made with instruments such as theodolites, spirit levels and leveling rods.

Such precise measurements are part of the Geodetic Survey’s National Spatial Reference System, which is the foundation for all types of surveys and allows government, industry and researchers to measure the position of objects in three-dimensional space.