Tag: geodesists

U.S. geodesists urgently needed

Luccio

With the last generation of trained geodesists either retired or getting ready to retire, we are at a critical stage of not being able to meet the geospatial needs of the future,” wrote David B. Zilkoski in his Nov. 1 Survey Scene column on our website. Few people, he pointed out, realize our $1 trillion geospatial economy — from precision agriculture to smart cities, from UAVs to location-based services — depends on geodesy. A collapse of geodesy would also harm our efforts to monitor rapid changes in the Earth’s surface due to sea-level rise, the deformation of tectonic plates, and temporal changes in the Earth’s water reservoirs.

Federal agencies, Zilkoski recalled, used to send staff to be trained in geodesy because they needed geodesists for such significant projects as the readjustment of the U.S. national horizontal and vertical geodetic networks. Now, while U.S. federal agencies still require this expertise to develop and refine geodetic models and tools, so do major U.S. companies for everything from routing delivery trucks to controlling earth-moving equipment to guiding tractors.

A January 2022 white paper by Mike Bevis and others titled “The Geodesy Crisis” reported that China has more geodesists than the rest of the world combined, and the number of Ph.D. geodesists in the entire Department of Defense, including the National Geospatial-Intelligence Agency (NGA), is approaching zero.

I discussed the geodesy crisis with Everett Hinkley, who works for the federal government, serves as a subject-matter expert on several high-level boards, and dubs himself a “concerned citizen geodesist.”

Matteo Luccio: How did we get here? Was it due in part to the success of GPS?

Everett Hinkley: The factors include:

1. In the early 1990s, the U.S. government largely disinvested in academic research and academic sponsorship in geodesy. Without student sponsorship, the few university programs that produced geodesy experts withered on the vine.

2. Math and science skills in U.S. public schools have declined.

3. More subtly, there was a subliminal and misguided notion that “Now that we have GPS, why do we need to continue to improve our geodetic models?”

ML: If left unaddressed, in what fields or applications will the crisis manifest first?

EH: In areas where precise positioning is critical: cadastral mapping, self-driving vehicles, sea-level rise (a growing danger) and others. The effects will be felt incrementally, at least at first.

ML: Are some geographic regions of the United States particularly vulnerable to some effects of the crisis due to high subsidence, drift or other ground movements/changes?

EH: Yes. The two areas that will show the first signs of divergence between actual and assumed locations are those that are tectonically active (both horizontally and vertically) and low-lying coastal ones.

ML: Besides funding, what could entice college students to enter the field?

EH: Basic marketing is needed by the geospatial community at large. We need to reach out to math “stars” in high school and let them know that pursuing a career in geodesy will guarantee them employment after graduating from college.

December 8, 2022
Who will survey?

Luccio

“Nothing can remain immense if it can be measured,” Hannah Arendt wrote in 1958 in The Human Condition. This could be the guiding inspiration for any geodesist or surveyor throughout history. In about 240 B.C., Eratosthenes became the father of geodesy by ingeniously measuring Earth’s circumference using the Sun, a well, a vertical column, the distance a camel caravan traveled from Syene to Alexandria and some basic mathematics. His estimate of 46,000 kilometers was 16% too large but remarkably close considering that he lacked any modern measuring tool. (For a great account of this epic feat, see John Noble Wilford’s The Mapmakers.)

Geodesy, a branch of applied mathematics, is concerned with accurately measuring and understanding three of Earth’s fundamental properties: its geometric shape, its orientation in space, and its gravity field. Earth’s true shape varies from the mathematically smooth surface of an ellipsoid due to local differences in its density that cause variations in the strength of the gravitational pull, in turn causing regions to dip below or bulge above a reference ellipsoid.

This undulating shape is the geoid, which geodesists have defined as the three-dimensional surface along which the pull of gravity is a specific constant. It serves as the zero-level surface for height measurements globally, and all GNSS are pegged to it. It is a hypothetical surface that essentially represents an extension of the idealized mean sea level over (actually, mostly under) Earth’s land surface. Unlike the surface of the oceans, however, it is unaffected by wind, waves, the Moon, or forces other than Earth’s gravity.

Surveyors are content with measuring much smaller portions of Earth’s surface, from single lots to national boundaries. Unlike Eratosthenes, they work with the latest fruit of modern science and technology — including GNSS receivers, robotic total stations, inertial measurement units, lidar, other sensors and unmanned aerial vehicles — and can measure distances with millimeter precision.

When I started in this business a little more than 20 years ago, we used to group GPS receivers by accuracy into three buckets: consumer grade, resource/mapping grade and survey grade. As accuracy has increased for all GNSS receivers, the boundaries between those categories, especially between mapping and surveying, have blurred. Additionally, we now have way more GNSS satellites — in some parts of the world, as many as 70 are in view at one time — and a panoply of public and private, ground-based and satellite-based corrections services.

So, surveyors have a growing set of tools, and they are constantly getting more accurate and more user-friendly.

Now, let me throw another number in the mix: 66. That is the average age of surveyors in the United States. In the short run, employment for surveyors hinges in part on the vagaries of the economy. In the long run, however, population growth and climate change will force large investments in infrastructure. On most construction sites, the first to arrive and the last to leave are the surveyors. We know what their tools are, but who will they be?

August 16, 2022
Number of trained US geodesists at crisis level

By David Zilkoski, contributing editor, survey scene

David B. Zilkoski

I attended The Ohio State University (OSU) to obtain my graduate degree in Geodetic Science in 1979. Therefore, I will admit that I am a little biased — once a geodesist, always a geodesist. The basic definition of geodesy is the applied science for determining the size and shape of the Earth, designing and realizing reference frames, and determining where you (and anything else) is on the Earth.

In OSU’s geodesy heyday (1960–1990s), many Americans trained were sent by federal agencies: National Geospatial-Intelligence Agency (NGA), NOAA/National Geodetic Survey (NGS), USGS, Army, Navy and Air Force. During the 1970s, NGS was sending two employees back to school every year. These agencies needed geodesists because they were undertaking major projects such as NGS’ to readjust the U.S. national horizontal (NAD83) and vertical geodetic (NAVD88) networks.

I was one of the employees that NGS sent to OSU to be trained to support the NAD83 and NAVD88.

The advancements in satellites and computers have enabled geodesy to expand into many different disciplines. Geodetic science and technology now underpin many sciences, large areas of engineering (such as driverless vehicles and drones), navigation, precision agriculture, smart cities and location-based services. Geodesy is actually more important than ever.

Today, the environment is different. U.S. federal agencies still need geodesists for developing enhanced and refined geodetic models and tools. However, major U.S. companies, such as Google and FedEx, as well as the automobile industry, precision farming companies and mining companies also need more accurate geodetic models, tools and algorithms. Therefore, these companies also need trained geodesists to perform important research on topics that address their specific geodetic requirements.

Today, OSU’s Geodesy Department is training very few American citizens. As the U.S. moves toward achieving geodetic-grade positioning in real-time in support of new applications such as driverless vehicles and drones, the number of trained geodesists should be increasing, not decreasing [Note: In 1990, there were 92 geodetic science graduate students. In 2019, there were 25; only three were U.S. citizens]. OSU and other universities need to educate and train the next generation of the nation’s scientific workforce of highly skilled research geodetic scientists that will expand industry’s research expertise.

The shortage of American geodesists poses a significant economic risk for the U.S. Europe and China train many more geodesists than the US. There are very few geodetic science programs in the U.S. today, and education in geodetic proficiencies has been fragmented. The OSU graduate program is one of few surviving geodetic science programs.

Users of geodetic products and services need to support geodetic departments in universities so that U.S. geodesy programs can grow to meet the geospatial demands of the future. The geospatial component of the economy is worth about $500 billion/year. So why are we allowing its foundational discipline to shrink in this country?

July 20, 2020