mOverlaps - Online in the Cloud

PROGRAM:

NAME

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

SYNOPSIS

mOverlaps [-e] [-d level] [-s statusfile] images.tbl diffs.tbl

DESCRIPTION

Analyze an image metadata table to determine a list of overlapping images. Each image is
compared with every other image to determine all overlapping image pairs. A pair of
images are deemed to overlap if any pixel around the perimeter of one image falls within
the boundary of the other image.

OPTIONS

-e Enables 'exact' overlaps mode, as opposed to the default approximate algorithm. The
default mode uses great-circle connecting lines between image corners to determine
which images overlap. Exact mode will instead check the edge pixels of every image
to determine which pixels are inside the others.

Although the default mode will occasionally report some incorrect overlaps, this is
not a concern since mDiff will detect and ignore these false positive results when
processing the table.

-d level
Turns on debugging to the specified level (1 or 2)

-s statusfile
Output and errors are sent to statusfile instead of to stdout

ARGUMENTS

images.tbl
Table of image metadata generated by mImgtbl.

diffs.tbl
Path of output table to be generated containing overlap information.

RESULT

Output table contains overlap information for each pair of overlapping images. The first
two columns are integer identifiers for the images from images.tbl; the second two give
their filenames, and the final column shows the filename of the FITS file that will be
generated using mDiffExec.

MESSAGES

OK [struct stat="OK", countnum-overlaps]

ERROR Cannot open status file: statusfile

ERROR Failed to open output filename

ERROR Invalid image metadata file: filename

ERROR Not enough information to determine coverages (CDELTs or CD matrix)

ERROR Need columns: cntr ctype1 ctype2 nl ns crval1 crval2 crpix1 crpix2 cdelt1 cdelt2
crota2 fname (equinox optional)

ERROR Bad WCS for image n

EXAMPLES

The following example looks at a list of 16 images, described in images.tbl, and
calculates which images overlap:

$ mOverlaps images.tbl diffs.tbl
[struct stat="OK", count=42]

Output file: diffs.tbl.

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