NAME

       mAdd - Re-project and mosaic your images, with background rectification

SYNOPSIS

       mAdd  [-p  imgdir]  [-n(o-areas)]  [-a  mean|median|count]  [-e(xact-size)]  [-d  level]  [-s statusfile]
       images.tbl template.hdr out.fits

DESCRIPTION

       Coadd the reprojected images in an input list  to  form  an  output  mosaic  with  FITS  header  keywords
       specified  in  a  header file. Creates two output files, one containing the coadded pixel values, and the
       other containing coadded pixel area values. The pixel area values can be used as a weighting function  if
       the output pixel values are themselves to be coadded with other projected images, and may also be used in
       validating the fidelity of the output pixel values.

OPTIONS

       -p imgdir
              Specifies path to directory containing reprojected images.  If the -p switch is not included, mAdd
              will look for the input images in the current working directory.

       -n     Co-addition  ignores  weighting  by  pixel  areas  and  performs  coaddition  based  only on pixel
              positions.  This flag refers to input images; the area file for the output  image  will  still  be
              created.

       -a type
              Select  type  of  averaging  to  be  done on accumulated pixel values (either mean or median).  To
              generate a map showing counts of how many times each pixel was overlapped by the input images, use
              count.

       -e     Enables  exact  size  mode.  The  output  image will match the header template exactly, instead of
              shrinking the output to fit the data.

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

       -s statusfile
              mAdd output and errors will be written to statusfile instead of stdout.

ARGUMENTS

       images.tbl
              ASCII table (generated by mImgtbl) containing metadata for all images to be coadded.

       template.hdr
              FITS header template to be used in generation of output FITS

       out.fits
              Name of output FITS image.

RESULT

       If successful, mAdd creates a FITS file out.fits that is a coadd of all  the  FITS  files  in  the  table
       images.tbl, according to the header template given.  A corresponding out_area.fits is also created.

MESSAGES

       OK     [struct stat = "OK", time=time]

       ERROR  MPI initialization failed

       ERROR  Invalid argument for -a flag

       ERROR  Cannot open status file: statusfile

       ERROR  Invalid image metadata file: filename

       ERROR  Need  columns: cntr,fname, crpix1, crpix2, cdelt1, cdelt2, naxis1, naxis2, crval1, crval2 in image
              list

       ERROR  Memory allocation failed

       ERROR  Too many open files

       ERROR  Input wcsinit() failed.

       ERROR  Failed to allocate enough memory for output arrays

       ERROR  Bad WCS in header template.

       ERROR  Images are not in same pixel space.

       ERROR  Template file not found.

       ERROR  FITS library error

       ERROR  general error message

EXAMPLES

       The following example runs mAdd on 4 FITS images, generating the output file mosaic.fits.  Related  files
       are images.tbl and template.hdr.

       $ mAdd -p proj images.tbl template.hdr output/mosaic.fits
              [struct stat="OK", time=1]

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.

       Although the memory limitation for output images has been overcome in versions 2.x and above of  Montage,
       it is still possible (though unlikely) to create an out-of-memory situation due to the size and number of
       input images. mAdd builds the output image one row at a time, and stores every pixel from any input image
       that contributes to that row in memory.

       If  you  have a large enough mosaic, it is almost always more efficient (and often easier on the user) to
       tile it. There are tools in Montage to help  with  this  and  these  have  been  brought  together  under
       mAddExec.  In  fact,  even  if  you  want  a single output image, it may be faster to do it in two steps:
       mAddExec to create a set of tiles, and then mAdd to make a  final  mosaic  from  these  tiles.  There  is
       absolutely no loss of information in doing this.

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.