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When Russell Congalton started analyzing the thematic accuracy of Landsat data during his internship at the U.S. Geological Survey’s (USGS) Earth Resources Observation and Science (EROS) Center in 1981, less than 10 years after the first satellite launched, the results weren’t necessarily popular. 

But his and others’ early work on determining the value of remote sensing data helped lay the groundwork to set benchmarks not only for gold standard Landsat data but all imagery collected from subsequent remote sensing platforms.

At Geo Week, EROS Chief of Staff Tim Glynn presented Congalton with the 2023 William T. Pecora Award for his thematic accuracy assessment work and other contributions to remote sensing science. ASPRS also handed out a Fellow award to EROS emeritus Gregory Stensaas and an outstanding service award to contractor Aparajithan Sampath, the KBR engineering lead for lidar, unmanned aircraft systems (UAS), and satellite system characterization programs at EROS.

Close up photo of man
Gregory Stensaas, ASPRS Fellow

Ensuring Data Accuracy

What links the three award winners is a dedication to ensuring that what you see is what you get when it comes to remote sensing data. That includes data from Landsat and other satellites, UAS (drones), or active sensing in the form of lidar, which bounces light off surfaces and then measures the resulting reflectance.

Accuracy was a major theme at Geo Week, which took place February 11-13, 2024, in Denver, Colorado. ASPRS (the American Society for Photogrammetry and Remote Sensing), one of the main sponsors of the event, continuously works to identify best practices and set standards for the industry. USGS experts like Stensaas and Sampath are deeply involved in that process. So is Congalton, whose research as Professor of Natural Resources and the Environment at the University of New Hampshire focuses on spatial data uncertainty, thematic map accuracy, and practical applications of remote sensing to solve natural resource problems.

All three have served on various ASPRS committees to help define standards for remote sensing, too many to list here. Stensaas, for example, was ASPRS’s primary data acquisition division director or deputy director several times, including a stint after he retired in May 2022. Currently, he is the standards committee chairman and is working on the ASPRS industry 10-year forecast. Sampath is the director of the lidar division and worked on the UAS addendum and lidar addendum to the ASPRS standards, among others. Congalton served as president of the ASPRS in 2004-2005, as the national workshop director from 1997 to 2008, and as editor-in-chief of Photogrammetric Engineering & Remote Sensing from 2008 to 2016.

A group of award winners
Aparajithan Sampath (back row, center) received an ASPRS  Outstanding Service Award at Geo Week.

Working with Data from Different Platforms

The sheer breadth of the award recipients’ experience highlights another trend featured at Geo Week: research using multiple remote sensing datasets, or as Congalton put it, “data fusion.” 

“There's no one single dataset that’s going to answer all the world’s questions,” Sampath noted. “So you have to bring in all kinds of data.” And the foundational value that gives data fusion scientific power turns right back to the core strength of ASPRS: setting standards. “The best way to do that is to make sure everything is as it is stated to be,” he said.

Stensaas mourned the timing of his retirement in respect to this trend. “It’s almost like a new birth in remote sensing with all the cool stuff happening today,” he said. “There’s a lot of change coming in the next few years in terms of interoperability of datasets and the use of higher resolution datasets along with the more global datasets and integrating those products together to do more automated science. I worked 30-something years in this environment, and now it’s just getting to the point where it’s really fun.”

Here's a closer look at the distinguished careers of the three recipients, mentioned in the order they received their awards.

Pecora Winner Dr. Russell G. Congalton

Two men admiring an award
Russell Congalton (left) is congratulated by EROS Chief of Staff Tim Glynn, who presented the Pecora Award at Geo Week. Photo credit: Shado Congalton.

As Professor of Natural Resources and Environment at the University of New Hampshire, Congalton combines two of his lifelong passions: teaching the next generation of scientists and helping create practical applications for remotely sensed data.

Congalton has been teaching at the university level for 39 years (including seven at the University of California, Berkeley), but he also has spent decades introducing younger students to the wonders of science, first through the GLOBE Program and then through AmericaView. For 12 years, he has been on the board of directors for AmericaView, which emphasizes K-college education as well as research in remote sensing, including a stint as chair, and is the director of New HampshireView.

While at Berkeley, Congalton helped start an environmental mapping company, and the firm’s first project was mapping old growth forests in Washington and Oregon to help protect the spotted owl. He continues to focus on solutions for natural resource problems at UNH, for example, facilitating remote sensing research projects to track blue algae in ponds and learn more about bear and loon habitat. 

His other research focus has been the accuracy of products created using remote sensing data. To that end, he co-wrote a book, Assessing the Accuracy of Remotely Sensed Data: Principles and Practices, with 2020 Pecora Award winner Kass Green in 1999, with subsequent editions in 2009 and 2019. “I really like the practical side of helping the user,” Congalton said, “the practitioner who’s actually going to use the map for their forest or rangeland or agricultural area.”

“I'm just so honored to get this award,” Congalton said. “I’m a big hockey fan, and so to me it’s the equivalent of winning the Stanley Cup.” 


Several people posing for a photo
Russell Congalton (center) stands with his colleagues from AmericaView after receiving the Pecora Award at Geo Week.
Professor and students in the field
Professor Congalton visits the field during research with University of New Hampshire students.
Two men hold an award
EROS Chief of Staff Tim Glynn (left) congratulates Gregory Stensaas on his ASPRS Fellow Award at Geo Week in Denver.

Gregory Stensaas, ASPRS Fellow

During his 13 years as a civilian working for the Army and Air Force, Stensaas researched a very different kind of remote sensing: how to exploit foreign infrared missile systems to create effective countermeasures for U.S. aircraft. 

While at EROS for 25 years, Stensaas worked on the Land Processes Distributed Active Archive Center (LP DAAC) and the upcoming Landsat Next mission. However, most of his time was spent as the USGS Project Manager for Calibration and Characterization, including the EROS Cal/Val Center of Excellence (ECCOE).

When he found out a month ago that he would receive the ASPRS Fellowship award, it spurred a few reflective thoughts. “When we learn about measures in school, the first thing that is mentioned is that every measurement has an error,” Stensaas said. “In remote sensing, we spend all of our time understanding that error and what the impact is to our Earth observation science. Throughout my career, understanding the remote sensing errors, across varying spectra, time and scale, was the key to understanding the certainty of our remote sensing science.”

Stensaas was touched and honored to become a Fellow. “It’s really your peers recognizing you as a mentor and a supporter of the remote sensing and photogrammetry arena,” he said.

Aparajithan Sampath, Outstanding Service Award

Several men present their awards
Aparajithan Sampath (third from left) accepts his Outstanding Service award at Geo Week in Denver.

Sampath became an ASPRS member in 2006, even before he started working at EROS in June 2009 in Sioux Falls, South Dakota. Now he works on ensuring that remote sensing data collected from uncrewed, aerial and satellite-based systems interact with each other seamlessly. He actively started contributing to ASPRS in 2013, including a presentation at this year’s Geo Week about quantifying the consistency of 3D lidar data at large scale using cloud computing and open-source software. 

In his view, ASPRS performs a standardization role that’s essential for all aspects of remote sensing. “We’re taking care of the industry and its needs and making sure it’s a platform for government, industry, academia, everybody to come together and exchange ideas and concerns,” Sampath said. “A part of the value of the data is hidden in the positional accuracy of the data.”

Sampath’s Outstanding Service Award was specifically for helping develop the ASPRS Positional Accuracy Standard for Digital Geospatial Data, Edition 2.

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