NAME

       mSubset  -  Filter  an  image metadata table down to those records representing FITS files that overlap a
       footprint on the sky

SYNOPSIS

       mSubset [-d level] [-f] [-s statusfile] images.tbl template.hdr subset.tbl

DESCRIPTION

       Generates a table of images that is a subset of the input table, containing only those images that  cover
       the area defined by a given FITS header.

OPTIONS

       -d level
              Turns on debugging to the specified level (1-3).

       -f     Fast mode - input file must include corners (-c flag in mImgtbl) to utilize this mode.

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

ARGUMENTS

       images.tbl
              ASCII table (generated by mImgtbl) containing metadata for image collection.

       template.hdr
              FITS header template defining the area of interest.

       subset.tbl
              Path  to  output  table,  which  will  contain only those FITS images covering the area defined by
              template.hdr.

RESULT

       [struct stat="OK", count=nin, nmatches=nout]

       where nin is the number of rows found in images.tbl, and nmatches is the number of  rows  in  subset.tbl,
       which includes only those images that overlap the area defined by template.hdr.

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.

Montage 5                                           Dec 2016                                          MSUBSET(1)