mProjectPP - Online in the Cloud

PROGRAM:

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] [-t threshold] [-X] 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.

-t threshold
If using a weight image; only use those pixels where the weight value is above
threshold.

-X Reproject the whole image even if part of it is outside the region of interest
(don't crop while re-projecting).

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]

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