NAME

       mTileImage - Create a set of tiled images or header templates from a FITS file or header

SYNOPSIS

       mTileHdr [-d] [-s statusfile] orig.hdr new.hdr nx ny ix iy [xpad [ypad]]

DESCRIPTION

       Takes  a header template file and creates another which represents one of a regular set of tiles covering
       the original.  The user specifies the tile gridding and which tile is desired.

       Only the NAXIS and CRVAL keyword lines are changed (pixel size and reference point location);  all  other
       keyword values will be inherited from the input header.

OPTIONS

       -d     Turns on debugging.

       -s statusfile
              Output and errors are sent to statusfile instead of to stdout

ARGUMENTS

       orig.hdr
              ASCII header template from which to derive tiled headers

       new.hdr
              Path to output header

       nx     Number of tiles in the x-direction

       ny     Number of tiles in the y-direction

       ix     Integer identifying the x location of the output tile on the grid (counting from 0)

       iy     Integer identifying the y location of the output tile on the grid (counting from 0)

       xpad   Number of pixels to overlap tiles in the x direction (optional; default is 0)

       ypad   Number of pixels to overlap tiles in the y direction (optional; default is 0)

RESULT

       [struct stat="OK", naxis1=xsize, naxis1=ysize, crpix1=xref, crpix2=yref]

       Where  xsize and ysize are the x and y dimensions of the image described by the output header, and crpix1
       and crpix2 are the new offset from the original reference pixel on the sky.

MESSAGES

       OK     [struct stat="OK", naxis1=xsize, naxis2=ysize, crpix1=xref, crpix2=yref]

       ERROR  Cannot open status file: statusfile

       ERROR  (nx,ny) have to be positive integers and (ix,iy) have to be in the range (0..nx-1, 0..ny-1)

       ERROR  Cannot open output template new.hdr

       ERROR  Bad template:orig.hdr

       ERROR  Bad template:new.hdr

       ERROR  Output wcsinit() failed.

EXAMPLES

       template.hdr is 850x850 pixels, and we want to generate the center tile out of 9 (3 by 3):

       $ mTileHdr template.hdr tile_1_1.hdr 3 3 1 1
              [struct stat="OK", naxis1=283, naxis2=283, crpix1=-283, crpix2=-283]

       tile_1_1.hdr has the same reference location and pixel scale as the input header, but a new pixel  offset
       (CRPIX) and size (NAXIS).

BUGS

       The drizzle algorithm has been implemented but has not been tested in this release.

       If a header template contains carriage returns (i.e., created/modified on a Windows machine), the cfitsio
       library will be unable to read it properly, resulting in the  error:  [struct  stat="ERROR",  status=207,
       msg="illegal character in keyword"]

       It  is  best  for  the  background  correction  algorithms  if  the area described in the header template
       completely encloses all of the input images in their entirety. If parts of input images are "chopped off"
       by  the  header  template,  the  background correction will be affected. We recommend you use an expanded
       header for the reprojection and background modeling steps, returning to  the  originally  desired  header
       size  for  the  final  coaddition.  The  default background matching assumes that there are no non-linear
       background variations in the individual images (and therefore in the overlap differences).  If  there  is
       any  uncertainty  in  this  regard, it is safer to turn on the "level only" background matching (the "-l"
       flag in mBgModel.

COPYRIGHT

       2001-2015 California Institute of Technology, Pasadena, California

       If your research uses Montage, please include the following acknowledgement: "This research made  use  of
       Montage.  It  is  funded  by  the  National  Science  Foundation  under Grant Number ACI-1440620, and was
       previously funded by the National Aeronautics and Space Administration's Earth Science Technology Office,
       Computation  Technologies  Project,  under  Cooperative  Agreement  Number  NCC5-626 between NASA and the
       California Institute of Technology."

       The Montage distribution includes an adaptation of the MOPEX algorithm developed at the  Spitzer  Science
       Center.