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You are here: GES DISC Home Giovanni - Interactive Visualization and Analysis Giovanni-3 Operation Technical Summary: Swath Center Pixel Extractor

Giovanni-3 Operation Technical Summary: Swath Center Pixel Extractor

Swath Center Pixel Extractor

The Swath Center Pixel Extractor Operation for Giovanni-3 is a special-purpose service designed to perform center-pixel subsetting on swath data. The service takes a series of swaths as an input and creates a corresponding series of output swaths. The output values are the result of applying center-pixel filtering to the input swaths.

Input parameters: Geophysical variables.

Output Description: Center-pixel filtered data in satellite swath format

Output Parameters: Same as input parameters

File Type: Both input and output files are HDF4.


  • Swath: 1- or 2-dimensional data structure.
  • Scan line: horizontal dimension of data structure.
  • Vertical level of measurement: vertical dimension of data structure.
  • Pixel -- individual data element of the data structure.

Service Description:

  1. Read in each swath (independently).
  2. Mask out bad/missing/fill values.
  3. Extract center pixel from each scan line; write to output file.
  4. Write corresponding time, latitude, longitude, and pressure level (if
    needed) to output file.

Algorithm Details: If the data contains a profile for each pixel, the profile for the center pixel is extracted.

Caveats/Warnings: All swaths are assumed to have the same width and number of vertical levels (where needed), but they may vary in the number of scan lines in the swath.

This Technical Summary page is under development -- for information on this operation while
the document is being prepared, please send a message to GES DISC Help.

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Last updated: Nov 10, 2011 12:08 PM ET