The team leader for advanced product software development of India’s National Remote Sensing Centre (NRSC) spent 10 days at EROS as part of the U.S.-India Professional Engineer and Scientist Exchange Program (PESEP). “I found it to be a really excellent program,” she said.

Tirumala appreciated the opportunity to connect with like-minded scientists who are interested in the accuracy of remote sensing data and the creation of products that benefit both researchers and the general public. 

Sources/Usage: Public Domain. View Media Details

She applied to the exchange program with specific interest in USGS EROS because of her experience in quality assurance for remote sensing data and in analysis ready data (ARD). 

Jeff Clauson, data quality lead for the EROS Calibration/Validation Center of Excellence (ECCOE), was instrumental in planning her visit and making her feel welcome. “It was great that USGS EROS had an opportunity to participate in PESEP by hosting Radhika,” he said.     

Her sessions at EROS were split between engineers and scientists from ECCOE and the Landsat Satellites Data System’s (LSDS) Science Research and Development (LSRD) projects. 

One of those sessions spurred a “Eureka!” moment for her: a conversation with ECCOE’s Mahesh Shrestha about the bidirectional reflectance distribution function, a way of analyzing how light bounces off surfaces. As Shrestha explained his approach, Tirumala realized that the procedure he was doing seemed familiar. “I was doing the same work to improve accuracy of one of my derived products” toward solving a particular problem, she said. Learning his next steps has direct applications for her own work.

Their collaboration was a textbook example for fulfilling the goals of PESEP, which aims to strengthen ties between scientists and engineers working on civil space programs in India and the United States. Partner agencies include the Indian Space Research Organization (ISRO), NASA, the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS). The EROS International Partnerships Project helped facilitate her stay in Sioux Falls.

Sources/Usage: Public Domain. View Media Details

Analysis Ready Data

The time devoted to accuracy with the science and engineering team was important, Tirumala said. In her current role overseeing new data products, calibration and validation are foundational. “Remote sensing is a multidisciplinary subject. Fundamental awareness about all subjects is needed to get an in-depth knowledge of what we are doing.”

At the moment, she is primarily focused on creating analysis ready data (ARD)­—data that needs little or no processing by people in the field who will use it for agriculture or conservation. In her opinion, the future of ARD will increase pressure to use more than one set of remote sensing data to get the best answers for, say, a farmer who wants to apply just the right amount of fertilizer or insecticide. 

To use different datasets together requires interoperability. Achieving that requires highly accurate calibration and validation, something ECCOE has set the gold standard for with Landsat satellite data, which is archived at EROS. “To build ARD harmonized datasets from different sensors, they need to match in radiometry and match in geometry,” Tirumala said. “My main focus was to understand and fill the gaps in what we have to build for our own ARD.”

The analysis ready data produced by NRSC is available on demand. Currently, a new land cover map for India is published every five years, but the goal is to release one annually using artificial intelligence and machine learning for a more automated approach. That’s similar to recent moves at EROS to release more data products annually. 

Tirumala also is eager to use machine learning for other endeavors, using “multiple sensors so that in near real time we can generate maps for disasters like floods as well as some rice crop mapping at a national level.”

Sources/Usage: Public Domain. View Media Details

Ideas and Memories

Some of the inspiration Tirumala found in Sioux Falls is for small changes that might work back in Hyderabad, where NRSC is located. She admired:

• The “meticulously quantified” storage and identification of satellite, aerial and other Earth observation data acquired throughout EROS’ history.
• The automation that allows just two people to manage the ground operations for a shift.
• The fact sheets that show how Landsat has benefited each state.

Her new friendships are equally important to her. “Maybe I am doing good work, but I do not know the international counterpart,” she said. “This is very important to make those kinds of connections for some particular focused topics.”

Tirumala’s one regret was that she didn’t visit sooner in her career. “It's not too late, but I should have come much earlier. Then the organization would have benefited much more. I’m very fortunate that I have had this opportunity.”

She was surprised by the prairie landscapes surrounding the EROS Center, which is 14 miles north of Sioux Falls. “So beautiful,” she said. “I miss my family. I’m just thinking we should come for a vacation.”