mExec - Create a 2MASS, SDSS or DSS mosaic based on a size and location

mExec  must be provided with FITS header information.  This can be in the form of a header template ("-f"
       flag), or the user can pass header text directly to the program ("-h" flag).

       -f region.hdr
              Path to header template used to create mosaic.

       -h header

              Provide header template as text input rather than point to a file; see sample  shell  script  that
              makes use of this option.

       survey band
              If not mosaicking user-provided data ("-r" flag), must select one of the following combinations of
              survey and band:

              2MASS [j, h, k] SDSS [u, g, r, i, z] DSS [DSS1, DSS1R, DSS1B, DSS2, DSS2B, DSS2R, DSS2IR]

       workspace-dir
              Directory  where  intermediate  files  will  be created.  If no workspace is given, a unique local
              subdirectory will be created (e.g.; ./MOSAIC_AAAaa17v)

       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.

       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                                            MEXEC(1)

       The mExec module is a mosaicking executive for 2MASS, SDSS, and DSS data.  It includes  remote  data  and
       metadata access.  Alternatively, users can mosaic a set of data already on disk.

       To create a small mosaic of the area around m31, located at coordinates "10.68469 41.26904":

       $ mHdr m31 0.3 m31.hdr
              [struct stat="OK", count="16"]

       $ mExec -o m31.fits -f m31.hdr 2MASS J tempdir
              [struct stat="OK", workspace="/path/to/tempdir"]

       To mosaic your own collection of data, contained in the directory "raw":

       $ mImgtbl raw raw.tbl
              [struct stat="OK", count=16, badfits=0]

       $ mMakeHdr raw.tbl raw.hdr

              [struct  stat="OK",  count=16,  clon=0.118289,  clat=0.118288, lonsize=0.236660, latsize=0.236660,
              posang=359.999756,     lon1=0.236618,     lat1=-0.000042,     lon2=359.999959,     lat2=-0.000041,
              lon3=359.999959, lat3=0.236618, lon4=0.236620, lat4=0.236617]

       $ mExec -o my_mosaic.fits raw.hdr workdir
              [struct stat="OK", workspace="/path/to/workdir"]

       OK     [struct stat="OK", workspace="workdir"]

       ERROR  Must have either header file (-f) or header text (-h)

       ERROR  Can't open original header template file: [region.hdr]

       ERROR  Can't open workspace header template file: [region.hdr]

       ERROR  Can't create proper subdirectories in workspace (may already exist)

       ERROR  Can't open header template file

       ERROR  Can't open expanded header file: [big_region.hdr]

       ERROR  survey has no data covering expanded area

       ERROR  survey has no data covering this area

       ERROR  No data was available for the region specified at this time

       ERROR  Bad WCS in input image

       ERROR  Can't open mosaic file: [mosaic.fits]

       ERROR  Can't open save file: [image.fits]

       ERROR  Output wcsinit() failed

       ERROR  ErrorfromanotherMontagemodule

       mExec - Create a 2MASS, SDSS or DSS mosaic based on a size and location

       -q     Use mProjectQL for reprojections.  Much faster but not quite flux-conserving.

       -r rawdir
              Provide  path  to  directory  containing  original  ("raw")  data  which  will  be reprojected and
              mosaicked.  Not necessary if using mExec to retrieve remote data  from  the  2MASS,  SDSS  or  DSS
              surveys.

       -n ntilex
              Number of output tiles to create along the X-axis - default is 1 for a single mosaicked image.

       -m ntiley
              Number of output tiles to create along the Y-axis - default is equal to ntilex.

       -l     "Level-only" flag (see mBgModel)

       -k     If retrieving data from a remote archive, the "keep" flag will leave the original data products on
              disk  after  generating  a  mosaic.   Without  this  flag, raw data will be deleted (unless it was
              provided by the user with the "-r" flag).

       -c     Remove all temporary files and intermediate data products.  Note: if not using the  '-o'  flag  to
              specify an output file, this will also remove mosaic.fits.

       -o output.fits
              Provide your own filename for the output mosaic.  Default filename is "mosaic.fits."

       -d level
              Print out additional debugging information (levels 1-4)

[structstat="OK",workspace="workspace-dir"]

       The output mosaic(s), and any intermediate files  (if  the  "-c"  flag  was  not  used)  will  be  inside
       workspace-dir.

       mExec  [-q] [-r rawdir] [-n ntilex] [-m ntiley] [-l] [-k] [-c] [-o output.fits] [-d level] [-f region.hdr
       | -h header] survey band [workspace-dir]