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                   Help notes for modis_L1A_extract
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Usage: modis_L1A_extract.csh L1A_file GEO_file SWlon SWlat NElon NElat Output_L1A_file [Output_GEO_file]

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The modis_L1A_extract.csh wrapper script extracts a Level 1A subscene from
an Aqua or Terra L1A and GEO file. If an output GEO file is specified, the
script will also create a GEO file corresponding to the new L1A subscene,
since the original GEO file will not work with the new subscene. The
region to be extracted must be specified as a box defined by a southwest
corner and northeast corner.

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Explanation of command line arguments:
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L1A_file (required)
Input MODIS Aqua or Terra L1A file to be extracted.

GEO_file (required)
Input MODIS Aqua or Terra Geolocation file.

SWlon (required)
Longitude of southwest corner of the box to be extracted.

SWlat (required)
Latitude of southwest corner of the box to be extracted.

NElon (required)
Longitude of northeast corner of the box to be extracted.

NElat (required)
Latitude of northeast corner of the box to be extracted.

Output_L1A_file (required)
Filename of the output L1A extracted subscene.

Output_GEO_file (optional)
Filename of the output GEO file corresponding to the new L1A subscene. If
Output_GEO_file is not specified, then no new GEO file will be created.

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