User's Guide

JSCGRID

Creates a Geometric Mapping Grid file for systematicly corrected MSS scenes

Function:

Creates a Geometric Mapping Grid file mapping from systematicly corrected MSS 4/5 data to the UTM map projection at 57 meter pixels.

Parameters:

INFILE

Input file. The input LANDSAT header file that contains the scene center and the path number. This file is created when running JSCIN. The default extension is ";lhdr".

OUTGRID

Output grid file. Output geometric mapping grid file containing the geometric mapping grid, as well as projection and framing information of the output space.

PRINT(TERM)

Output destination. The destination of the projection information and resulting corner coordinates.

  = --:        No Report
  = TERM:      Terminal.  Output is sent to the user's
               terminal.
  = LP:        Line printer.  Output is sent to the
               printer defined by $PRINTER.
  = Filename:  User-supplied filename.  Output is sent
               to the user-supplied file with the 
               extension ".prt".

Examples:

1. LAS> jscgrid infile=scene1 outgrid=geogrid print=(term,lp)

   The LANDSAT header file SCENE1;LHDR is opened and the lat/long centers of the scene and the path number are read. All information printed is written to both the terminal and a printer. The resulting geometric mapping grid is calculated and written to GEOGRID;GRID.

Description/Algorithm:

The input parameters are retrieved from TAE. The LANDSAT header file is opened and the center latitude and longitude of the scene are read along with the path number of the scene. JSCGRID first calculates the corner coordinates of the systematically corrected input image. Since the Space Oblique Mercator (SOM) projection is very close to the geometry of a systematically corrected scene, SOM coordinates are calculated for each corner. These SOM corners are based on the input pixel size, center lat/long, inclination angle and the rotation at the latitude of scene center. Next, the output space in the UTM projection, but still along track (i.e, not rotated north-up), is calculated. Then a first-order polynomial transformation between each projection space and the corresponding line/sample coordinates are calculated. A geometric mapping grid is then created by mapping from output line/sample to UTM coordinates to lat/long to SOM coordinates to input image line/sample coordinates. Projection information is written to the geometric mapping grid. RESAMPLE uses the grid to perform the image warping and writes projection information to the resulting image's DDR.

Nonfatal Error Messages:

None.

Fatal Error Messages:

1. [jscgrid-fatal] Fatal error encountered

   The error message that is displayed immediately preceding this message is the specific error that was encountered. Processing is terminated.

2. [jscgrid-alloc] Error allocating dynamic memory

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

3. [jscgrid-open] Error opening temporary file

   An error was encountered in attempting to open a temporary file. Check the protections on the directory.

User Notes:

1. JSCGRID uses the JSC universal format as used by ESA, Thailand and others. 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.

2. It is assumed the geometric mapping grid will be used in RESAMPLE with the full scene from tape to produce the final image with fully-valid DDR.

3. Related routines are JSCIN, JSCPROC, and DSPASSOC.