LP DAAC Project Scientist Tom Maiersperger still remembers the question clearly, back five years or so ago, when NASA's Land Processes Distributed Active Archive Center (LP DAAC) at EROS was just starting to explore the idea of a new data extraction tool.
Landsat ARD Now Part of AppEEARS’ Data Extraction Capability
A Boston University professor had stopped by during a conference to eyeball Maiersperger’s poster about something that would come to be known as the Application for Extracting and Exploring Analysis Ready Samples (AppEEARS) tool. Interesting, the man mused, especially its possibility for time series work with NASA’s Moderate Resolution Imaging Spectrometer (MODIS) and other datasets.
“But,” he asked Maiersperger, “what about Landsat?”
He need wonder no more. On May 15th this year, Landsat Analysis Ready Data (ARD) joined more than 100 other datasets in an intuitive AppEEARS extraction tool that enables users to study single geographic points across the planet, or to go larger and sample expansive areas. Now those users will be able to combine Landsat ARD surface reflectance with specified bands and time ranges from scores of other geospatial datasets.
“Really, almost from the minute we started pulling the veil back on this (AppEEARS) capability, we’ve had people asking about Landsat,” Maiersperger said. “When we talk about this tool at workshops or conferences, a lot of people say, ‘Hey, wouldn’t it be great if we had Landsat data so we can have it integrated with MODIS and other data products we have?’”
EROS Science and Applications Branch Chief John Dwyer says AppEEARS will in fact be another good, viable option for visualizing time-series stacks made possible through Landsat ARD.
“Absolutely,” Dwyer said. “We asked the DAAC to look into doing this as yet another way of looking at new and innovative interfaces to get at the data. And then one of the questions from our vantage point becomes, ‘If we put (Landsat ARD) into the cloud, can those tools be ported out there ... to help with that.’”
Maiersperger said NASA’s Earth Observing System Data and Information System (EOSDIS) has already been talking to the LP DAAC about prioritizing datasets to take to the cloud. Research and development could begin on prototyping an architecture that allows AppEEARS to consume data from on-premise storage and cloud storage in the next year or so, he said.
“Maybe some of the services migrate to the cloud,” Maiersperger said. “There’s a lot of interesting things we need to figure out, but I think (the cloud) represents another phase in the evolution of (AppEEARS).”
It will be interesting to see how the user community reacts to the ability to meld Landsat ARD with other available datasets in AppEEARS, such as MODIS, Web-Enabled Landsat Data (WELD), and elevation datasets only available from the LP DAAC, Maiersperger said.
But that’s not all AppEEARS has to offer. The LP DAAC has also added MODIS snow data products from the National Snow and Ice Data Center (NSIDC) DAAC to its data extraction capabilities, and a selection of datasets from NASA’s Soil Moisture Active Passive (SMAP) mission as well. There are population data products from the Socioeconomic Data and Applications Center (SEDAC). And meteorological products like precipitation and temperature measurements from Daymet out of the Oak Ridge National Lab.
Having Landsat ARD as an option “should drive the usage (of AppEEARS) much higher, for sure,” Maiersperger said, adding, “though at this point, it’s hard to predict the rate of adoption.”
He noted that roughly 10 percent of LP DAAC users are taking advantage of AppEEARS. In the last six months, the number of unique users acquiring data from the LP DAAC has averaged in the 7,000 to 8,000 range, Maiersperger said. During the same period, the number using AppEEARS jumped from 400 to 500 up to around 800 unique users, with about half of those being new to the extraction tool. His team is just starting to see the use of AppEEARS in citations for scientific manuscripts, he said.
“There is sort of a consciousness moment where people realize (AppEEARS) is a real thing that exists in the world,” Maiersperger said. “It’s like when people—say students or professors, for example—are talking about it at any given conference or venue, and they’re saying, ‘Hey, go use this for your study.’”
Of course, Landsat ARD in AppEEARS wouldn’t be possible without the collaboration of the LP DAAC and the Landsat side of EROS, Maiersperger said. Landsat collaborators put a lot of work into the back end to prepare Landsat ARD to be functional in the extraction tool. Those collaborators prepared, unzipped, and reformatted Landsat ARD to work in the Open-source Project for a Network Data Access Protocol, or OPeNDAP, which is a set of capabilities next to the data that AppEEARS connects to and needs to pull out data to be worked on, Maiersperger said.
LP DAAC team members then had to ensure that the User Interface, Application Programming Interface, and AppEEARS functionality were all properly hooked up and working appropriately on the data.
“I am ... very proud of the way the technical teams came together and worked on this effort for the last 1½ years and interacted with the user community to get to a point of release,” said LP DAAC Project Manager Chris Doescher, who expects the Landsat ARD-AppEEARS collaboration “to be a huge success.”
If nothing else, it has been a good example of projects across EROS pulling together for a greater good, Maiersperger said. After all, part of the impetus for bringing the LP DAAC to EROS almost three decades ago was the integration of other important land remote-sensing datasets with Landsat, he said.
To have Landsat ARD and AppEEARS come together now, he added, “is a very natural extension of the kinds of things we’ve been doing for a long time.”