As high-precision GNSS horizontal and vertical data becomes less expensive to collect, greater attention must be paid when reconciling vertical datasets. In 2013, I wrote two articles entitled ...

Part 1 of this column appeared in the June Survey Scene newsletter, Part 2 appeared in the August newsletter. Upcoming Survey Scene newsletters will carry additional columns in this series. In my ...

The joint NASA-German Aerospace Center Gravity Recovery and Climate Experiment (Grace) mission has released its first science product, the most accurate map yet of Earth’s gravity field. Grace is the ...

The Earth’s geoid is the shape the planet would assume if its surface were made of water. Naturally, there’s little dispute over the shape of the geoid over the oceans, where it varies by only 100 ...

For years, researchers have tried to pinpoint how an area deep in the Indian Ocean with lower gravitational pull came to be. A team in India may have figured it out. The area in question is called the ...

Figure 1: Relationship between the geoid and seismic tomography. The best-fitting model (Fig. 2a) was found by a systematic parameter search (Supplementary Figs 1–5). The eastern hemisphere geoid low ...

Have you ever thought to use a clock to identify mineral deposits or concealed water resources within the Earth? An international team headed by astrophysicists Philippe Jetzer and Ruxandra Bondarescu ...

[UPDATE (April 5, 2011): It turns out some of the descriptions I used below to describe a geoid were not accurate. I refer you to this page at the University of Oklahoma for a good description. I’ve ...

Take a clay model of Earth and squish it with your fingers, and the result may look similar to the geoid — the latest and best-ever map of our planet's gravitational field. The latest Earth gravity ...