l1aextract_seawifs |

### l1aextract_seawifs

Creates an extracted L1A SeaWiFS file.

Location
Details
Command Line Usage

#### Location

SeaDAS-Toolbox -> SeaDAS Processors -> extractor

#### Details

l1aextract_seawifs is used to create a sub-scene file by extracting and/or sub-sampling from an original SeaWiFS L1A file. The output file is an HDF file and has the same format as the original L1A file.

The l1aextract_seawifs GUI allows the user to specify either the pixel/line ranges, the lat/lon ranges, or the two lat/lon corner points for the subscene to be extracted.

l1aextract_seawifs GUI

Arguments/Keywords

UI Element Name | Type | Description | Required/Optional | Default Value
infile | Text Field | Input MODIS Aqua or Terra L1A file to be extracted, or an L1A filelist for multiple file extraction. (Required) | Required |
ofile | Text Field | Output filename for the L1A extracted subscene. A default ofile name is generated by the program. | Required |
swlon | Text Field | Longitude of southwest corner of the box to be extracted. | Conditional |
swlat | Text Field | Latitude of southwest corner of the box to be extracted. | Conditional |
nelon | Text Field | Longitude of northeast corner of the box to be extracted. | Conditional |
nelat | Text Field | Latitude of northeast corner of the box to be extracted. | Conditional |
spix | Text Field | Starting pixel in infile for extracting. | Conditional |
epix | Text Field | Ending pixel in infile for extracting. | Conditional |
sscan | Text Field | Starting line in infile for extracting. | Conditional |
escan | Text Field | Ending line in infile for extracting. | Conditional |
pix_sub | Text Field | Pixel sub-sampling rate. | Optional |
sc_sub | Text Field | Scan line sub-sampling rate. | Optional |

Actions/Buttons

UI Element Name | Type | Description
Browser Button | Button | Selects infile/ofile
Compute PixLines from LonLat | Button | Derives spixl, epixl, sline, and eline arguments from swlon, swlat, nelon, and nelat arguments by internally executing the lonlat2pixline program.
Load Parameters ... | Button | Reads in previously saved parameters and populates the fields in GUI.
Store Parameters ... | Button | Saves the current arguments in GUI in a file.
Run | Button | Executes the l1aextract_seawifs command with arguments provided in the UI.
Cancel | Button | Closes current processor GUI.
Apply | Button | Makes current arguments effective.
Open in SeaDAS | Checkbox | If selected, the ofile will be added to the open products list right after its generation.
? | Button | Displays the help content of the current command.

#### Command Line Usage

    Usage: <l1aextract_seawifs> infile spix epix sscan escan pix_sub sc_sub outfile
       where:
    	infile   - input l1a data HDF file
    	spix     - start pixel number
    	epix     - end pixel number
    	sscan    - start scan line
    	escan    - end scan line
    	pix_sub  - pixel subsampling rate
    	sc_sub   - scan line subsampling rate
    	outfile  - output file name

    NOTE: Start and End pixel/scanline will be set to input file's nsamp
    	 and nrec respectively, if the given values are out of range.