NAME

       mBestImage - Determine which image covers a location "best"

SYNOPSIS

       mBestImage [-d level] images.tbl ra dec

DESCRIPTION

       Given a list of images and a position on the sky, determine which image covers the location "best" (i.e.,
       the one where the position is farthest from the nearest edge).

OPTIONS

       -d debug
              Turn on debugging to the specified level (1 or 2)

ARGUMENTS

       images.tbl
              Input table of image metadata (as generated by mImgtbl).

       ra     RA of location of interest (in degrees)

       dec    Declination of location of interest (in degrees)

RESULT

       [struct stat="OK", file="filename", edgedist=distance]

       or

       [struct stat="OK", file="filename", url="fileurl", edgedist=distance]

       where filename is the name of the "best" image found in images.tbl and  distance  is  measured  from  the
       point of interest to the nearest edge of the image.  If the input table included a URL column, the output
       message will also include the image's URL.

MESSAGES

       OK     [struct stat="OK", file="filename", url="fileurl", edgedist=distance"]

       OK     [struct stat="OK", file="filename", edgedist=distance"]

       ERROR  Invalid image metadata file: images.tbl

       ERROR  Need columns: cntr and fname; ctype1 ctype2 nl ns crval1 crval2 crpix1 crpix2  cdelt1  cdelt2  and
              crota2 or cd matrix / ra dec ra1 ... dec4

       ERROR  Bad WCS for image fitsfile

       ERROR  No image covers this position.

EXAMPLES

       Given  a  table  of  image  metadata  describing  images  covering  a  0.5  by 0.5 degree area around m31
       (2mass_m31_j.tbl), narrow it down to the image  which  includes  the  best  coverage  of  one  particular
       location:

       mBestImage 2mass_m31_j.tbl 10.7 41.2
              [struct stat="OK", file="2mass-atlas-971024n-j0080033.fits", edgedist=0.008436]

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.