Provided by: montage_5.0+dfsg-1_amd64 
NAME
mProjectPP - Re-project FITS images
SYNOPSIS
mProjectPP [-z factor] [-d level] [-b border] [-s statusfile] [-o altout.hdr] [-i altin.hdr] [-h hdu] [-x
scale] [-w weightfile] [-W fixed-weight] [-t threshold] [-X] [-b border-string] in.fits out.fits
template.hdr
DESCRIPTION
mProjectPP reprojects a single image to the scale defined in an alternate FITS header template generated
(usually) by mTANhdr. 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. This area image goes
through all the subsequent processing that the reprojected image does, allowing it to be properly coadded
at the end.
mProjectPP performs a plane-to-plane transform on the input image, and is an adaptation of the Mopex
algorithm and developed in collaboration with the Spitzer Space Telescope. It provides a speed increase
of approximately a factor of 30 over the general-purpose mProject. However, mProjectPP is only suitable
for projections which can be approximated by tangent-plane projections (TAN, SIN, ZEA, STG, ARC), and is
therefore not suited for images covering large portions of the sky. Also note that it does not directly
support changes in coordinate system (i.e. equatorial to galactic coordinates), though these changes can
be facilitated by the use of an alternate header.
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 levels
greater than 1, it's recommended to redirect the output into a text file.
-b border
Ignores border pixels around the image edge when performing calculations.
-s statusfile
Output and errors are written to statusfile instead of being written to stdout.
-[i|o] alternate.hdr
Specifies an alternate FITS header for use in mProjectPP calculations, allows substitution of
psuedo-TAN headers created by mTANHdr.
-h hdu Specify the FITS extension to re-project if the FITS image is multi-extension.
-x scale
Multiple the pixel values by scale when reprojecting. For instance, each 2MASS image has a
different scale factor (very near 1.0) to correct for varying magnitude-zero points.
-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.
ARGUMENTS
in.fits
Input FITS file to be reprojected.
out.fits
Path to output FITS file to be created.
template.hdr
FITS header template to be used in generation of output FITS
RESULT
Two files are created as output: the reprojected FITS file (out.fits), and an "area" image
(out_area.fits). See the image reprojection algorithm for more information.
MESSAGES
OK [struct stat="OK", time=seconds]
ERROR Drizzle factor string (string) cannot be interpreted as a real number
ERROR Cannot open status file: statusfile
ERROR Weight threshold string (threshold) cannot be interpreted as a real number
ERROR Flux scale string (scale) cannot be interpreted as a real number
ERROR Border value string (string) cannot be interprted as an integer or a set of polygon vertices
ERROR Border value (value) must be greater than or equal to zero
ERROR HDU value (hdu) must be a non-negative integer
ERROR Could not set up plane-to-plane transform. Check for compliant headers.
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 Input and output must be in the same coordinate system for fast reprojection
ERROR All pixels are blank
ERROR Input image projection (projection) must be TAN, SIN, ZEA, STG or ARC for fast reprojection
ERROR Output image projection (projection) must be TAN, SIN, ZEA, STG or ARC for fast reprojection
ERROR Template file [template.hdr] not found
ERROR Image file in.fits is missing or invalid FITS
ERROR Weight file weightfile is missing or invalid FITS
ERROR FITS library error
EXAMPLES
$ mProjectPP rawdir/real_orig.fits projdir/base_unity.fits templates/galactic_orig.txt
[struct stat="OK", time=14]
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.
mProjectPP is only suitable for use on projections which can be approximated by tangent-plane projections
(TAN, SIN, ZEA, STG, ARC), and is therefore not suited for images covering large portions of the sky.
Also note that it does not directly support changes in coordinate system (i.e. equatorial to galactic
coordinates), though these changes can be facilitated by the use of an alternate header.
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.