Soil moisture is a key variable in understanding land surface hydrology and in modeling ecosystems, weather, and climate. Among NSIDC’s most popular data sets is the “AMSR-E/Aqua Daily L3 Surface Soil Moisture, Interpretive Parameters, & QC EASE-Grids” (AE_Land3) data set. This data set is distributed in HDF-EOS format and one of the biggest hurdles encountered by many users is simply learning how to display the data. Here are some tips on how to get started.
The HDF Group provides sample code for access and visualization of HDF data into IDL, MATLAB, and NCL. Access to the sample code for AMSR-E HDF data is provided on the HDF Group’s HDF-EOS Comprehensive Examples Web page.
If you are more familiar with GeoTIFF format, you may choose to utilize the HDF-EOS to GeoTIFF (HEG) Tool to convert AMSR-E Daily Soil Moisture HDF data into GeoTIFF format. This tool also allows you to subset the data with spatial or parameter constraints, as well as change the output projection. These HEG Tool services are also available as an option when ordering these data through the Reverb search and order interface. Instructions on how to use these data services in Reverb can be found in this Online Support article.
If you are interested in importing the data into ArcGIS, you can either use the GeoTIFF files generated by the HEG Tool or downloaded from Reverb, or you can perform a few steps to import the native HDF-EOS files into ArcMap. Using the ArcToolbox, you can easily extract a data field from an HDF file and save it in a different raster format that you are more familiar with. Instructions detailing how to do this can be found in this Online Support article.
AMSR-E L3 Daily Soil Moisture plot, 07/01/2002.
Hierarchical Data Format (HDF) supports a variety of data types and allows for the transfer and manipulation of scientific data across diverse operating systems and computer platforms. It was developed by the HDF Group at the University of Illinois and is the standard data format for all NASA Earth Observing System (EOS) data.
A variety of HDF data are distributed at NSIDC, including data from the AMSR-E, MODIS, and GLAS sensors as well as the NISE data set.
Despite the versatility of HDF, some data users have had difficulty in reading and displaying HDF data and often ask if we have sample code for reading HDF data in programs such as IDL and MATLAB.
Fortunately, the HDF Group provides sample code for access and visualization of HDF data into IDL, MATLAB, and NCL. Access to the sample code for NSIDC HDF data is provided on the HDF Group’s HDF-EOS Comprehensive Examples Web page.
Also note that this information can be found in our Online Support under the AMSR-E, MODIS, GLAS, and NISE forums.
The NASA IceBridge Project is comprised of airborne data over the most dynamic areas of the Arctic, Greenland, Alaska and Antarctica. The data gathered by this project are unique in that they are spatially referenced by flight lines, flights are flown during approximately 3-month campaigns, and data are collected by a wide variety of instrumentation.
The NASA IceBridge Data Portal provides a single location from which one can get an overview of all the IceBridge data sets. It allows for map-based visualization of the flight paths via polar views of the Northern and Southern Hemispheres. Using a variety of filters and image overlays, one can visualize, search and download IceBridge data campaigns. NSIDC recently added some new capabilities to the IceBridge Data Portal. These new features include:
- A simpler display which allows users to hide and move informational windows
- The ability to filter results by selecting one or more instruments
- A tar-on-the-fly option for downloading complete directories of data at once
- New map layers for enhanced visualization including:
- Mosaic of Greenland (MOG)
- Shaded Relief DEM
- MEaSUREs Velocity Map
- Mosaic of Antarctica (MOA)
- Antarctic Bedrock DEM
- Radarsat Antarctic Mapping Project (RAMP)
Begin your search for IceBridge data through the newly improved NASA IceBridge Data Portal.