.TH MDIFFFITEXEC 1 "Dec 2016" "Montage 5" "Montage"
.SH NAME
mDiffFitExec \- Run mDiff and mFitplane for each record found by mOverlaps

.SH SYNOPSIS
mDiffFitExec [\-d] [\-l(evel-only)] [\-n(o-areas)] [\-p projdir] [\-s \fIstatusfile\fP]


diffs.tbl region.hdr diffdir fits.tbl

.SH DESCRIPTION
Using the table of overlaps found by \fBmOverlaps\fP, \fBmDiffFitExec\fP runs both \fBmDiff\fP and \fBmFitplane\fP for each record.  The fitting parameters are written to a file to be used by \fBmBgModel\fP.

.SH OPTIONS
.TP
\-d
Turns on debugging
.TP
\-l
Only find image background level differences, not slope offsets.
.TP
\-p
Directory containing projected images.
.TP
\-s \fIstatusfile\fP
Writes output message to \fIstatusfile\fP instead of to stdout

.SH ARGUMENTS
.TP
diffs.tbl
Overlap table generated by \fBmOverlaps\fP, listing all the image pairs that overlap.
.TP
region.hdr
FITS header template that was used to reproject the images.
.TP
diffdir
Working directory for the difference images.
.TP
fits.tbl
Output table of difference parameters.

.SH RESULT
Generates a table, \fBfits.tbl\fP, containing all the information generated by running \fBmDiff\fP for the image pairs in diffs.tbl and then \fBmFitplane\fP on each difference image.  \fIcount\fP is the number of overlaps in diffs.tbl, \fIdiff_failed\fP is the number that generated an error condition for \fBmDiff\fP, \fIfit_failed\fP is the number that generated an error condition for \fBmFitplane\fP, and \fInwarning\fP is the number that generated a warning.

.SH MESSAGES
.TP
ERROR
Cannot open status file: \fIstatusfile\fP
.TP
ERROR
Can't open output file.
.TP
ERROR
Invalid diffs metadata file: \fIdiffsfile\fP
.TP
ERROR
Need columns: cntr1 cntr2 plus minus diff
.TP
ERROR
\fIsvc library error\fP

.SH EXAMPLES
.PP
First, diffs.tbl is generated for a collection of reprojected images using \fBmOverlap\fP:
.TP
$ mDiffFitExec \-d \-p projected diffs.tbl gal.hdr diffs fits.tbl
[struct stat="OK", count=6, diff_failed=0, fit_failed=0, warning=0]
.PP
Output file: fits.tbl.

.SH BUGS
The drizzle algorithm has been implemented but has not been tested
in this release.
.PP
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"]
.PP
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.

.SH COPYRIGHT
2001-2015 California Institute of Technology, Pasadena, California
.PP
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."
.PP
The Montage distribution includes an adaptation of the MOPEX algorithm
developed at the Spitzer Science Center.