How to Import SMAP HDF Data Into ArcGIS

This How To guide, relevent only to ESRI ArcMap10.5 and later versions, will outline the steps to follow in order to properly project and visualize global** SMAP L3 and L4 HDF data in ArcGIS. However, if you are running ArcMap10.4.1, there is a patch available for download that will allow you to follow the instructions below after installation. If you are working in older versions of ArcMap, the best course of action is to utilize NASA's Earthdata Search tool to order SMAP data in GeoTIFF format. If you are in need of guidace for the Earthdata tool, please see our video tutorial showing you how to search for and order SMAP data. This example (using SPL4SMGP) will show you how to import, geolocate, and scale global smap HDF data.

  1. Create a File Geodatabase
    Begin ArcMap10.5 with a blank map. Open the Catelog window and, where you prefer a new workspace to be created, Right Click on some folder connection > New > File Geodatabase

     
  2. Add New Mosaic Dataset to Geodatabase
    Once your File Geodatabase is created and named how you want it, it's time to add an empty data placeholder. Right click on your geodatabase > New > Mosaic Dataset.



    In the dialogue box that opens, name the new dataset appropriately and assign the proper Projected Coordinate System. In the case of SPL4SMGP, the Coordinate System is "WGS_1984_NSIDC_EASE-2.0_Global". Select "OK" and wait for the layer to be added. It should now show up in the Table of Contents.

     
  3. Add SMAP Variable to the New Mosaic Dataset
    Now, it's time to add data to the Mosaic. Right clicking on your new Mosaic Dataset, select "Add Rasters...". In the "Add Rasters to Mosaic Dataset" window that pops up, perform the following operations:
    1. On the Raster Type dropdown menu, select HDF
    2. In the Workspace dropdown menu under Input Data, select File.
    3. Select the Folder Connection icon next to the blank file field, and select the HDF dataset of interest.

       
    4. Now, select a specific variable. In the same window, click the Properties icon to the far right of the Raster Type dropdown menu where you selected HDF in step 3.a. Select your variable from the list (making sure that you select the check box rather than simply highlighting) and wait for the "Interpolate Irregular Data" field to auto-fill. We recommend not changing the cell size or the scheme from Nearest Neighbor.

       
    5. Select OK for both windows and wait for data to be loaded to the map.
       
  4. Calculate Statistics on the New Raster
    The raster should now be on display within the Map pane. However, ArcGIS does not yet know what the min / max values are and defaults to the maximum range. To auto-fit the data, right click again on your new Mosaic Dataset > Enhance > Calculate Statistics. A new window will pop up where you have the option of adjusting the amount of data in your raster to be used in the calculation with the "Number of Rows/Columns to Skip". We recommend using the default of 1, so that all cells are used and the true minimum and maximum are obtained.


    Read more about how changing the default values will impact the result of the calculation here: https://blogs.esri.com/esri/arcgis/2013/10/11/skipfactor/


Done! Best of luck in your future analyses.


Regards,
NSIDC User Services

*Not applicable for these Level 3 northern hemisphere products
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