Knowledge Base

How to extract point and area samples of SMAP data using AppEEARS

This step-by-step tutorial demonstrates how to access NASA SMAP data using the Application for Extracting and Exploring Analysis Ready Samples (AppEEARS). AppEEARS allows users to obtain and display point and area data using spatial, temporal, and layer subsets. SMAP data from NSIDC that are accessible in AppEEARS include SPL3SMP, SPL3SMP_E, SPL3FTP, SPL4CMDL, SPL4SMGP (31 March 2015 to 3 June 2018). Time series data are plotted on several graphs within the interface and can also be downloaded in .csv (point data) or GeoTiff and NetCDF (area data) formats.

Step 1: Access the AppEEARS interface, https://lpdaacsvc.cr.usgs.gov/appeears/. An Earthdata login in required.

Step 1 - SMAP AppEEARS

Step 2: Under the Extract dropdown, choose Point Sample.

Area samples can also be chosen but the steps and options are slightly different than what are outlined in this article.

Step 3: Choose Start a new request.

Users can also copy a previous request or upload a JSON file. Both options are beneficial to loading previous order details, such as lat/long coordinates, temporal coverage, and data layers.

Step 3 - SMAP AppEEARS

Step 4: Fill in the data submission details.

For this article, use the following details:

  1. Name your project: SPL3SMP Test
  2. Start Date: 01-01-2016
  3. End Date: 12-31-2016
  4. Enter product: SPL3SMP
  5. Add layers of interest: Soil_Moisture_Retrieval_Data_AM_soil_moisture and Soil_Moisture_Retrieval_Data_PM_soil_moisture. Click on + to add individual layers and to remove individual layers.
  6. Enter coordinates of points you wish to obtain data for. A .csv file can be loaded if the format matches what is described on the page. Or, use the Add a coordinate tool on the map to populate the coordinates field with where you click on the map. For this article, simply copy/paste the coordinates below:

Aspen, 39.1911, -106.8175

Boulder, 40.0150, -105.2705

Denver, 39.7392, -104.9903

Durango, 37.2753, -107.8801

Grand Junction, 39.0639, -108.5506

Fort Collins, 40.5853, -105.0844

La Junta, 37.9850, -103.5438

Steamboat Springs, 40.4850, -106.8317

  1. Click Submit

Step 4 - SMAP AppEEARS

Step 5: Under Explore, track the progress of a submission

An email confirmation will also be sent when the order is completed.Step 5 - SMAP AppEEARS

Step 6: Explore the results:

  1. When completed, click on the contents button (highlighted above) to view results and compare layers.
  2. The Temporal Comparison tab displays data values from individual sites and data layers over time. Hint: The time scales can be adjusted in the Time Series graph. Also, hover over a point on the graph to view the value and date. Step 6b - SMAP AppEEARS
  3. The Layer Comparison tab allows comparison of each data layer with a time series and scatter plot graph at individual sites.Step 6c - SMAP AppEEARS
  4.  The Categorical Overview tab displays a box and whisker plot of all sites for individual layers for the entire time series. Hover over individual plots to view related data values. Step 6d - SMAP AppEEARS

Step 7: Download all data results

Back in the Explore tab, click the Download all Contents of the request button. Deliverables include the following:

  • .csv file with all the data
  • .json file with order details
  • .txt file with a list of all science granules used in the order as well as links to the data at NSIDC
  • .xml file of related metadata

Step 7 - SMAP AppEEARS

For more detailed instructions of how to use AppEEARS, please visit https://lpdaacsvc.cr.usgs.gov/appeears/help

Last Updated April 2018

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