Last month the New York Times covered a subject that you’d expect to be too technical for the general reader: NOAA’s efforts to recalibrate elevation data as part of its update to the National Spatial Reference System, expected in 2022 or 2023. The height modernization program corrects local elevation data—which was last updated in 1988—by using GPS and gravity mapping. The Times article looks at the real-world implications of this effort, which will have the greatest impact the further west and north you go (see map above), from bragging rights about mountain elevation to whether your community is in a floodplain. [MAPS-L]

Previously: NATRF2022 Datum Coming to North America in 2022.

Little is publicly known about the true scope of the information that Hough and his team captured, or the ingenuity they displayed in securing it, because their mission was conducted in secret, and the technical material they seized circulated only among military intelligence experts and academics. But it was a vast scientific treasure—likely the largest cache of geographic data the United States ever obtained from an enemy power in wartime.

The data seized by Hough’s team went on to form the basis of the ED50 geodetic datum, which in turn led to the Universal Tranverse Mercator system.

The ocean floor is still very much terra incognita: only 5 to 15 percent of it has been mapped via bathymetry. But using military satellite measurements of the Earth’s shape and gravity field, a new map of the ocean floor has been created. “The result of their efforts is a global data set that tells where the ridges and valleys are by showing where the planet’s gravity field varies. […] Shades of orange and red represent areas where seafloor gravity is stronger (in milligals) than the global average, a phenomenon that mostly coincides with the location of underwater ridges, seamounts, and the edges of Earth’s tectonic plates. Shades of blue represent areas of lower gravity, corresponding largely with the deepest troughs in the ocean.”