Extractors |

### Extractors

Creates an extracted data product.

##### Location

SeaDAS-Toolbox -> SeaDAS Processors -> extractor

Description
GUI Usage
Command Line Usage

#### Description

The Extractor GUI serves as a front-end to several product extractors provided with SeaDAS:

- l1aextract_modis
- l1aextract_viirs
- l1aextract_seawifs
- l2extract

The extractor GUI initially displays a default window, as shown in the image below, to accept input parameters/options. Once an input file is selected, the program will decide which extractor to be used based on the input file type and display customized GUI for each specific extractor.

#### GUI Usage

##### l1aextract_modis

Arguments/Keywords

UI Element Name | Type | Description | Required/Optional | Default Value
infile | ifile | Input MODIS L1A file to be extracted, or an L1A filelist for multiple file extraction. | Required |
ofile | ofile | Output filename for the L1A extracted subscene. A default ofile name is generated by the program. | Required |
swlon | float | Longitude of southwest corner of the box to be extracted. | Conditional |
swlat | float | Latitude of southwest corner of the box to be extracted. | Conditional |
nelon | float | Longitude of northeast corner of the box to be extracted. | Conditional |
nelat | float | Latitude of northeast corner of the box to be extracted. | Conditional |
spixl | int | Starting pixel in ifile for extracting. | Conditional |
epixl | int | Ending pixel in ifile for extracting. | Conditional |
sline | int | start line (1-based) | Conditional |
eline | int | end line (1-based) | Conditional |

##### l1aextract_viirs

Arguments/Keywords

UI Element Name | Type | Description | Required/Optional | Default Value
infile | ifile | Input VIIRS L1A file to be extracted, or an L1A filelist for multiple file extraction. | Required |
ofile | ofile | Output filename for the L1A extracted subscene. A default ofile name is generated by the program. | Required |
swlon | float | Longitude of southwest corner of the box to be extracted. | Conditional |
swlat | float | Latitude of southwest corner of the box to be extracted. | Conditional |
nelon | float | Longitude of northeast corner of the box to be extracted. | Conditional |
nelat | float | Latitude of northeast corner of the box to be extracted. | Conditional |
spixl | int | Starting pixel in ifile for extracting. | Conditional |
epixl | int | Ending pixel in ifile for extracting. | Conditional |
sline | int | start line (M-band resolution, 1-based). | Conditional |
eline | int | end line (M-band resolution, 1-based). | Conditional |

##### l1aextract_seawifs

Arguments/Keywords

UI Element Name | Type | Description | Required/Optional | Default Value
infile | ifile | Input L1A HDF file to be extracted, or an L1A filelist for multiple file extraction. | Required |
ofile | ofile | Output filename for the L1A extracted subscene. A default ofile name is generated by the program. | Required |
swlon | float | Longitude of southwest corner of the box to be extracted. | Conditional |
swlat | float | Latitude of southwest corner of the box to be extracted. | Conditional |
nelon | float | Longitude of northeast corner of the box to be extracted. | Conditional |
nelat | float | Latitude of northeast corner of the box to be extracted. | Conditional |
spix(l) | int | Starting pixel in ifile for extracting. | Conditional |
epix(l) | int | Ending pixel in ifile for extracting. | Conditional |
sline(sscan) | int | Starting line in ifile for extracting. | Conditional |
eline(escan) | int | Ending line in ifile for extracting. | Conditional |
pix_sub | int | Pixel sub-sampling rate. | Optional | 1
sc_sub | int | Scan line sub-sampling rate. | Optional | 1

##### l2extract

Arguments/Keywords

UI Element Name | Type | Description | Required/Optional | Default Value
infile | ifile | Input L2 file to be extracted | Required |
ofile | ofile | Output filename for the L2 extracted subscene. A default ofile name is generated by the program. | Required |
swlon | float | Longitude of southwest corner of the box to be extracted. | Conditional |
swlat | float | Latitude of southwest corner of the box to be extracted. | Conditional |
nelon | float | Longitude of northeast corner of the box to be extracted. | Conditional |
nelat | float | Latitude of northeast corner of the box to be extracted. | Conditional |
spix(l) | int | Starting pixel in ifile for extracting. | Conditional |
epix(l) | int | Ending pixel in ifile for extracting. | Conditional |
sline(sscan) | int | start scan line (1-based) | Conditional |
eline(escan) | int | end scan line (1-based) | Conditional |
pix_sub | int | Pixel sub-sampling rate | Optional | 1
sc_sub | int | Scan line subsampling rate | Optional | 1
prodlist | string | Comma separated product list | Optional |

Actions/Buttons

UI Element Name | Type | Description
Browser Button | Button | Selects infile/ofile
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 extract 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

##### l1aextract_modis

    This is version 0.76 of l1aextract_modis (compiled on Aug 21 2025 23:36:51)

    Usage: l1aextract_modis infile spixl epixl sline eline outfile
       where:
    	infile   - input MODIS L1A datafile
    	spixl    - start pixel number (1-based)
    	epixl    - end pixel number (1-based)
    	sline    - start line (1-based)
    	eline    - end line (1-based)
    	outfile  - output file name

    Note: Enter line number NOT scan number!

##### l1aextract_viirs

    l1aextract_viirs 0.998 (Aug 21 2025 23:36:30)

    l1aextract_viirs infile spixl epixl sline eline outfile

      where:
        infile  - input VIIRS L1A file

        spixl   - start pixel (1-based)
        epixl   - end pixel (1-based)
        sline   - start line (M-band resolution, 1-based)
        eline   - end line (M-band resolution, 1-based)
        outfile - output VIIRS L1A extract file

    To extract entire scan line set both spixl and epixl to 0

##### l1aextract_seawifs

    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.

##### l2aextract

    This is version 3.2 of l2extract (compiled on Aug 21 2025 23:37:44)
    l2extract 3.2 (Aug 21 2025 23:36:53)
    Usage: l2extract argument-list
       or: l2extract ifile spix epix sline eline pix_sub sc_sub ofile <prodlist>

      This program takes a product (or products if netCDF output) from an L2 file
      and does the extraction

      The argument list is a set of keyword=value pairs.  Arguments can
      be specified on the command line, or put into a parameter file, or the
      two methods can be used together, with command line overriding.

    The list of valid keywords follows:

       help (boolean) (alias=h) (default=false) = print usage information
       version (boolean) (default=false) = print the version
            information
       dump_options (boolean) (default=false) = print
            information about each option
       dump_options_paramfile (ofile) = print
            information about each option to paramfile
       dump_options_xmlfile (ofile) = print
            information about each option to XML file
       par (ifile) = input parameter file
       ifile (ifile) = input L2 filename
       ofile (ofile) (default=output) = output filename
       product (string) = comma separated list of products, empty string outputs all
            all products
       spix (int) (default=1) = start pixel number (1-based).
       epix (int) (default=-1) = end pixel number. -1 = last pixel (1-based).
       sline (int) (default=1) = start line (1-based).
       eline (int) (default=-1) = end line.  -1 = last line (1-based).
       suite (string) = suite for default parameters
       verbose (boolean) (default=false) = more information reporting
       wavelist (string) = comma separated list of 3D wavelengths and/or colon
            separated nnn:nnn range of wavelengths, empty string outputs all
            3D wavelengths (i.e. wavelist=353,355,358,360,360:370,450:600,700)