SMOS Grid Point Export

SMOS Grid Point Export

The Grid Point Export Command can be used to export the data of selected DGG grid points. The data can be exported either as CSV formatted text file (where individual values are separated by a semicolon) or as Earth Explorer formatted subsets.

Grid Point Export in SNAP

Source Products: Either the SMOS product selected in SNAP, or all SMOS products residing in a directory of the file system can be used for exporting. The search for SMOS products may optionally include subdirectories.

Region of Interest: There are three possibilities for specifying a region of interest (ROI) considered for export:

• A ROI defined by a geometry
• A ROI defined by the grid points under the pins of the SMOS product selected in SNAP
• A ROI defined by a latitude-longitude box

Target File: The file, which receives the exported data. For exporting as CSV, the target file must be a normal file while for creating Earth Explorer subsets, it must be a directory. The amount of data can be huge, depending on the ROI selected and the number of source products traversed.

The file name of each Earth Explorer subset is generated from the file name of its source, with sensing start and stop times matching the actual snapshots in the subset, if the source contains the necessary snapshot information.

Grid Point Export on the Command Line

The command line tool for exporting grid point data resides in the bin directory of your SNAP installation. Depending on your system platform, type

    ${S3TBX_HOME}/bin/smos-gp-export.bat
  

    ${S3TBX_HOME}/bin/smos-gp-export.sh
  

or

    ${S3TBX_HOME}/bin/smos-gp-export.command
  

in order to obtain a usage message. The grid points, for which data is exported can be defined by either a latitude-longitude box or a latitude-longitude point. For instance, type

    smos-gp-export.sh -point 1.0 7.0 SM_TEST_MIR_SCLF1C_20070223T061043_20070223T061105_310_001_0
  

for exporting the data of a single grid point. Type

    smos-gp-export.sh -box -10.0 10.0 -20.0 20.0 SM_TEST_MIR_SCLF1C_20070223T061043_20070223T061105_310_001_0
  

for exporting all grid points contained in a latitude-longitude box. The target file can defined by means of the -o option. If a target file is not defined, the output is printed to the console. For example, type

    smos-gp-export.sh -point 1.0 7.0 -o export.csv SM_TEST_MIR_SCLF1C_20070223T061043_20070223T061105_310_001_0
  

If the target file is a directory, the grid point data are exported in form of EE formatted files, which all reside in the target directory. The file name of each subset product is generated from the file name of its source product. For example, type

    smos-gp-export.sh -point 1.0 7.0 -o exportDir SM_????_MIR_SCLD1C_2010*
  

Using more than a single SMOS product as source is possible. The usual shell completion can be used to specify multiple product files. For example, type

    smos-gp-export.sh -point 1.0 7.0 -o export.csv SM_????_MIR_SCLD1C_2010*

or

    smos-gp-export.sh -point 1.0 7.0 -o exportDir SM_????_MIR_SCLD1C_2010*

to export only SMOS land dual-polarisation science products for 2010.