NAME

       mProject - Re-project FITS images

SYNOPSIS

       mProject  [-z  factor]  [-d level] [-s statusfile] [-h hdu] [-x scale] [-w weightfile] [-W
       fixed-weight]  [-t  threshold]  [-X]  [-b  border-string]  [-e(nergy-mode)]  [-f]  in.fits
       out.fits hdr.template

DESCRIPTION

       mProject  reprojects  a  single  image to the scale defined in a FITS header template file
       (read more about header templates here). The  program  produces  a  pair  of  images:  the
       reprojected image and an "area" image consisting of the fraction input pixel sky area that
       went into each output pixel.  The  "drizzle"  algorithm  is  implemented.   The  algorithm
       proceeds by mapping pixel corners (as adjusted by drizzle, if called) from the input pixel
       space to the output pixel space, calculating overlap area  with  each  output  pixel,  and
       accumulating  an  appropriate fraction of the input flux into the output image pixels.  In
       addition, the appropriate fraction of the input pixel area is accumulated  into  the  area
       image  pixels.   Projection  of  points  from  input  pixel space to output pixel space is
       calculated in two steps: first map from input pixel space to sky coordinates;  second  map
       from sky coordinates to output pixel space.

       One  situation  that has happened often enough to warrant special note:  It is possible to
       define a FITS header with the reference location off the  image.   In  particular,  people
       often  reference  cylindrical  projections (e.g., CAR, CEA) to location (0.,0.) (e.g., the
       Galactic center).  This is not wrong in itself but does  lead  to  extremely  large  pixel
       offsets  (e.g.,  in  the hundreds of thousands).  Related to this, if you extract a header
       from an image with large offsets of this type, it is unlikely that you can  simply  change
       projection  types without also adjusting the reference location/offsets.  Most likely, you
       will end up with the reproject data all being off-scale.

OPTIONS

       -z factor
              Processing is done utilizing the drizzle algorithm.  factor  is  a  floating  point
              number; recommended drizzle factors are from 0.5 to 1.

       -d level
              Causes  additional debugging information to be printed to stdout.  Valid levels are
              1-5 (for higher debugging levels, it is recommended to redirect  the  output  to  a
              file).

       -s statusfile
              Output and errors are written to statusfile instead of being written to stdout.

       -h hdu Use the specified FITS extension (default is to use the first HDU with image data)

       -x scale
              Apply a correction factor of scale to each pixel

       -w weightfile
              Path to a weight map to be used when reading values from the input image.

       -W fixed-weight
              Use constant weight value for the whole image.

       -t threshold
              Pixels with weights below threshold will be treated as blank.

       -X     Makes  the  output region (originally defined in the header template) big enough to
              include all of the input images

       -b border-string
              Define a border width or border pixel corners outside of which all pixels  are  set
              to NaN.

       -e     Process  the  data  as  total  energy rather than the default energy density (scale
              values by relative pixel areas).

       -f     Output the full region requested even if there is a border of NULL values  (default
              is to shrinkwrap to just the pixels with values).

ARGUMENTS

       in.fits
              Input FITS file to be reprojected.

       out.fits
              Path of output FITS file to be created.

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

RESULT

       Two files are created as output: the reprojected FITS file (out.fits), and an "area" image
       (out_area.fits) which records the amount of coverage (in output pixel space)  provided  by
       the input images.

MESSAGES

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

       ERROR  Drizzle factor string (string) cannot be interpreted as a real number

       ERROR  Weight threshold string (string) cannot be interpreted as a real number

       ERROR  Flux scale string (string) cannot be interpreted as a real number

       ERROR  Cannot open status file: statusfile

       ERROR  HDU value (hdu) must be a non-negative integer

       ERROR  No overlap

       ERROR  Not enough memory for output data image array

       ERROR  Not enough memory for output area image array

       ERROR  Output wcsinit() failed.

       ERROR  Input wcsinit() failed.

       ERROR  FITS library error

       ERROR  All pixels are blank

       ERROR  Template file not found

       ERROR  Image file in.fits missing or invalid FITS

       ERROR  Weight file weightfile missing or invalid FITS

EXAMPLES

       $ mProject rawdir/real_orig.fits projdir/base_unity.fits templates/galactic_orig.txt
              [struct stat="OK", time=143]

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.