User's Guide

JSCIN

Reads Johnson Space Center (JSC) formatted tapes

Function:

Reads Johnson Space Center (JSC) formatted tapes and creates a LAS image. The image on tape may be windowed or subbanded when copied. Header files and ancillary records may also be written to disk.

Parameters:

COMMENT
Description of tape. A text string sent to the operator's terminal describing the tape to be mounted. COMMENT should contain the tape library identification number and a short description of the tape. This will allow the operator to ensure the correct tape is mounted.

OUT
Output image. The name of the output LAS image. The size and data type of the output image are determined by information from the universal header file on tape or the values specified in WINDOW and BANDS.

WINDOW(--)
Window specification. Specifies the starting line, starting sample, number of lines, and number of samples to be processed. The default indicates the entire image is processed.

BANDS(--)
Band number(s). The image bands on tape to be processed. The default indicates that all bands present on tape are processed.

WRTDSK(HDR)
Write to disk. Specifies which associated files/or records are to be copied from tape. See User Note 1. 

  = ANC:  Ancillary records.  The ancillary data block
          is written to disk.
  = HDR:  Header files.  The universal header and the 
          LANDSAT header are written to disk.

Example:

  1. LAS> jscin comment="please mount r0179. thailand" out="tai.image" window=(100,100,1024,1024) bands=(2 4)

    The tape r0179 is mounted on a drive. The user has specified a 1024x1024 window be copied from tape starting at line 100, sample 100. Only bands 2 and 4 will be copied to TAI.IMAGE. By default, the header files will also be copied to the disk files TAI.IMAGE;UHDR and TAI.IMAGE;LHDR.

Description/Algorithm:

A JSC formatted tape contains three files; a universal header file, a LANDSAT header file, and an image data file. The image data file is band interleaved by line (BIL) and may be considered in terms of data sets. A data set consists of <x> physical records where <x> is the number of image bands. Each physical record within the data set contains the record number, the ancillary data block, and the image data. The ancillary data block is identical for each record within the same data set. See User Note 1 for information regarding the content of the universal header file, LANDSAT header file, and ancillary records.

JSCIN begins the process by getting the input parameter values and opening the tape drive unit. The universal header and the LANDSAT header files are then read from tape and written to disk if requested. These files will be associated with the output LAS image and will have the extensions ";UHDR" and ";LHDR". The universal header file is parsed to determine the image size, image data type, total physical record length, and the size of the ancillary record within each physical record.

A LAS image is created and opened for output. For each line and band to be read, the image data is extracted from the physical record and written to disk. If specified, the ancillary records for each data set are written to a disk file associated with the output image with the extension ";ANC".

Nonfatal Error Messages:

  1. [jscin-window] Specified window is too large

    The specified window is larger than the image data on tape. The window has been reset to be the intersection of the window specification and the actual image.

  2. [jscin-nonfatal] Nonfatal error encountered

    A nonfatal error was encountered during processing. The error message displayed immediately preceding this message is the specific error encountered. Processing continues.

  3. [jscin-band] Band <x> does not exist on tape

    The band entered in BANDS does not exist on tape. Processing will continue with the remaining bands being copied from tape.

Fatal Error Messages:

  1. [jscin-alloc] Error allocating dynamic memory

    An error occurred allocating memory. Rerun, and if the error persists, contact the LAS system manager.

  2. [jscin-tape] Error encountered reading tape

    An error was encountered reading the tape. Verify that the tape is good and conforms to the JSC tape format.

  3. [jscin-fatal] Fatal error encountered

    A fatal error was encountered during processing. Processing is terminated. The error message displayed preceding this message is the specific error encountered.

  4. [jscin-dtype] Data type not handled

    The data type of the image data on tape is not currently handled. Only BTYE and INTEGER*2 are currently handled. Contact the LAS system manager.

  5. [jscin-zero] Zero total bands specified

    The bands specified in BANDS did not include any bands on tape. Respecify BANDS and rerun.

  6. [jscin-window] Value for WINDOW must be greater than or equal to 1

    Window specification must be greater than or equal to 1. Respecify WINDOW parameter and rerun.

User Notes:

  1. The universal header file consists of a single record containing information about the mission, the sensor parameters, the scene identification and the layout of the image data file. The LANDSAT header file specifies the scene on tape and the processing options which have been applied to the data. The ancillary data contains the channel status indicator, satellite time code and the sampled calibration wedge data. The LANDSAT header is used by JSCGRID to create a geometric mapping grid.

  2. Related functions are JSCGRID and DSPASSOC.

  3. For further information on the JSC format, consult the Format Specifications for Canadian LANDSAT MSS System Corrected Computer Compatible Tape, Murphy, J., Research Report 79-2, August 1979