Data Tool in Focus: AppEEARS

AppEEARS allows users to subset data spatially, temporally, and by layer, reducing the amount of data they need to download.

The volume of data in NASA’s Earth Observing System Data and Information System (EOSDIS) never stops growing. On September 30, 2021, the total amount of data in the EOSDIS archive, including data migrated to the cloud, was 59.24 petabytes (PB). On September 30, 2022, this volume was 71.64 PB—an increase of 12.4 PB in one year. By 2030, the volume of data in the EOSDIS archive is projected to surpass 500 PB thanks to high-data-volume missions such the Surface Water and Ocean Topography (SWOT) mission, which launched in December 2022, and the forthcoming NASA-Indian Space Research Organization Synthetic Aperture Radar (NISAR) mission, which is scheduled for launch in 2024.

Yet, as the EOSDIS archive grows and grows, data users are looking for ways to simplify and streamline their methods of data discovery and analysis. This is precisely what the Application for Extracting and Exploring Analysis Ready Samples (AppEEARS) tool from NASA's Land Processes Distributed Active Archive Center (LP DAAC) was designed to do.

AppEEARS provides access to a wide array of geospatial data products (e.g., elevation, land cover, soil moisture, vegetation, and daily meteorological variables) for the contiguous U.S. and the world from several EOSDIS Distributed Active Archive Centers (DAACs), including the LP DAAC, the National Snow and Ice Data Center DAAC (NSIDC DAAC), the Oak Ridge National Laboratory DAAC (ORNL DAAC), and the Socioeconomic Data and Applications Center (SEDAC). In doing so, it saves users a lot of time by enabling access to multiple datasets from the same platform. This array of datasets includes a wide range of environmental variables derived from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA’s Terra and Aqua satellites, the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the joint NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite, the Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) on the International Space Station, NASA's Soil Moisture Active Passive (SMAP) mission, Daymet, Harmonized Landsat Sentinel-2 (HLS), and socioeconomic variables from the Gridded Population of the World Version 4 (GPWv4) collection.

AppEEARS allows users to subset data spatially, temporally, and by layer, significantly reducing the amount of data and time they need for analysis. Two types of sample requests are available: point (geographic coordinate pairs) and area (vector polygons).

The AppEEARS Point Sampler allows users to input tens and even hundreds of geographic coordinates, select specific data variables of interest from NASA Earth science data, and set constraints to receive time series information. AppEEARS Point Sample request outputs include not only files containing the extracted data values and their associated quality information, but also important supplementary files containing information including links to the source data files and summary statistics for the data extracted. Sample request outputs are downloaded as comma separated value (CSV) files, which significantly reduce the amount of data users have to download to their local machine. Users also can explore data values, trends, and relationships within the AppEEARS interface using a variety of interactive charts and graphs.

AppEEARS point sample example showing a MODIS Land Surface Temperature (LST) time series for a location near Phoenix, AZ, USA. Seasonal temperature differences are easy to see in the bottom graph, with cooler temperatures in the winter and warmer temperatures in the summer (temperature values are shown in kelvins). Credit: NASA LP DAAC/USGS EROS. 

The AppEEARS Area Sampler allows users to subset data spatially (by input polygons), temporally, and by layer. It also can create mosaics and transform extracted outputs to user selected geographic or projected coordinated reference systems. In addition to returning area-specific raw data values, the Area Sampler also returns associated quality data as well as summary files containing data quality definitions and summary statistics relating to data visualizations offered within the Area Sampler. Ultimately, AppEEARS gives users access to petabytes of Earth science data and allows users to subset specific geographic areas along with setting variable and temporal constraints, freeing them from the need to download gigabytes or terabytes of data.

In addition to the features mentioned above, AppEEARS provides the ability to:

  • Input latitude/longitude coordinate pairs or select point locations from a map to retrieve data for specific point locations;
  • Upload polygon shapefiles or GeoJSON-formatted files with multiple features, or draw a polygon on a map to retrieve mosaicked data across geographic areas;
  • Transform data from native format (e.g., HDF) to GeoTIFF or NetCDF4 and from native projection to a selection of common projections;
  • Explore requested samples within the application using several different graphing and charting options;
  • Easily access data quality descriptions for individual pixels.

How to Access AppEEARS

AppEEARS is a collaborative effort between several NASA DAACs and the USGS Earth Resources Observation and Science (EROS) Center. It is hosted in and can be accessed via the Earthdata Cloud. Note: The use of AppEEARS requires a NASA Earthdata login.

Additional Resources

For more information on getting started with AppEEARS, please see the tool’s documentation.

AppEEARS also has an application programing interface (API). To learn more, visit the AppEEARS API Documentation or work though the AppEEARS tutorials on how to use AppEEARS in Python or in R.

Users can also view the following tutorials: An Introduction to the AppEEARS Point Sampler and An Introduction to the NASA AppEEARS Area Sampler. In addition, the NASA Earthdata webinar Using NASA’s AppEEARS to Slice and Dice Big Earth Data provides instruction on the use of AppEEARS to subset, reformat, and reproject Earth science data.

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