User's Guide

ORBLN

Continually set bad data to zero within AVHRR archive images

Function:

Perform line detection and set bad data to zero in AVHRR archive images. Time discrepancies that may exist within the header files are also fixed. These processes are accomplished in preparation for orbital stitching of the images.

Parameters:

INFILE
Input file. The file containing the list of orbital stitching information. Refer to User Note 1 for the input file format.

STRSCENE(--)
Starting scene ID. The scene ID within INFILE at which processing should begin. If STRSCENE is not found within INFILE, no scenes will be processed. If unspecified, processing will begin at the first scene ID in INFILE.

ENDSCENE(--)
Ending scene ID. The scene ID within INFILE at which processing should end. If ENDSCENE is not specified or the specified ID is not found within INFILE, processing will continue to the end of INFILE.

LOGFILE(--)
Log file. Name of the log file that the processing messages will be appended to. The default is orbln.log in ADAPSLOG.

Example:

  1. LAS> orbln infile=ss050110.txt strscene=ah11030192133424 endscene=ah11030192221812

    The input stitch list "ss050110.txt" is searched from scene "ah11030192133424" to scene "ah11030192221812" for scenes which are on disk but not yet line detected. The subdirectory "lndetect" in the directory ADAPSORB is searched for the AVHRR archive images previously identified within the stitch list. When an image is found, line detection is performed. The resulting line detected images are placed in the subdirectory "process" in the ADAPSORB directory. The orbital stitch file "ss050110.txt" is updated to reflect a line detected status for the scenes as they are processed.

Description/Algorithm:

Continually set bad data to zero and correct headers in AVHRR archive images. The input stitch list is continually searched for AVHRR images which need to be processed. When one of these images is found in the "lndetect" subdirectory under the ADAPSORB directory, it is processed by FIXTIMES and LNDETECT, and then moved to the "process" subdirectory of ADAPSORB. The specified orbital stitch list is updated to reflect the completion of the line detection for the appropriate image. If an error occurs in any of these steps, the image is moved into the "error" subdirectory of ADAPSORB. Images within the "lndetect" subdirectory of ADAPSORB will be processed in the order which they occur within the stitch list. This procedure may be started concurrently with ORBREAD and ORBSTITCH via the ORBSTART procedure, or it may be executed independently. Messages will be logged in the file "orbln.log" within the ADAPSLOG directory.

Nonfatal Error messages:

    Refer to FIXTIMES and LNDETECT

Fatal Error messages:

  1. [orbln-fatal] Fatal error encountered

    A fatal error was encountered. The message displayed preceding this message is the error that was encountered.

  2. [orbln-odir] Error determining the output directory

    An error occurred trying to determine the directory in which to place the resultant image. Verify that the environment variable ADAPSORB has been defined.

  3. [orbln-sfil] Error determining the stop file

    The stop file name cannot be determined. Verify that the environment variable ADAPSTABLES has been defined.

  4. [orbln-exst] Input file does not exist

    The specified input stitch list does not exist. Verify the specification of INFILE.

  5. [orbln-exe] Error returned from half orbit grouping

    An error occurred while attempting to read a half orbit of information from the stitch list. Verify that the stitch list has not been corrupted.

  6. [orbln-ffil] Error determining the input scene

    An error occurred looking for a scene on disk that exists according to the input stitch list. Verify that the "lndetect" directory exists below the ADAPSORB directory.

  7. [orbln-imgn] Error assigning image names

    An error occurred while determining the name of the image to line detect. Contact the system administrator if this error is repeated.

  8. [orbln-lock] Error locking the input image

    An error occurred while attempting to lock the image. Verify that the image exists and has not already been locked.

  9. [orbln-fixterr] Error occurred in fixtimes

    An error occurred while fixing the image header file. Verify that the image header file has not been corrupted.

  10. [orbln-lndetect] Error occurred in lndetect

    An error occurred while line detecting the image. Refer to the specific error message from LNDETECT.

  11. [orbln-cmdel] Error occurred deleting input files

    An error occurred deleting the input files from disk. Verify that the image exists with the appropriate file permissions.

  12. [orbln-lockfil] Error occurred unlocking input file

    An error occurred unlocking the input file. Verify that the lock file exists with delete permission.

  13. [orbln-updt] Error updating the orbital stitch file

    An error occurred attempting to update the stitch list. Refer to the error message generated by ORBEDIT.

User Notes:

  1. The expected format of the input file is as follows:

    
    tapeid mth acqdate  start  stop ceos st d a source flg
    031185 AH 04/01/92   5332  10408 NGC 11 D A  31376
    019990 AH 04/01/92  34636  35718 HBT 11 D A  37446
    020403 AH 04/01/92  35703  40438 TSV 11 D A  38496
    031272 AL 04/01/92  41800  42906 NOA 11 D A  31435
    019990 AH 04/01/92  52626  54118 HBT 11 D A  37447
    020403 AH 04/01/92  53416  54728 TSV 11 D A  38497
             .                            .
             .                            .
             .                            .
    
    
    The header is read until the line beginning with "tapeid" has been encountered. Valid lines of data are expected following this line.

  2. Refer to the orbital stitching overview for more detailed information.