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Astro::Correlate::Method::RITMatch - Correlation using RIT Match.


  ( $corrcat1, $corrcat2 ) = Astro::Correlate::Match::RITMatch->correlate( catalog1 => $cat1, catalog2 => $cat2 );


This class implements catalogue cross-correlation using the RIT Match application.


General Methods


Cross-correlates two catalogues.

  ( $corrcat1, $corrcat2 ) = Astro::Correlate::Method::RITMatch->correlate( catalog1 => $cat1,
                                                                            catalog2 => $cat2 );

This method takes two mandatory arguments, both Astro::Catalog objects. It returns two Astro::Catalog objects containing Astro::Catalog::Star objects that matched spatially between the two input catalogues. The first returned catalogue contains matched objects from the first input catalogue, and ditto for the second. The Astro::Catalog::Star objects in the returned catalogues are not in the original order, nor do they have the same IDs as in the input catalogues. A matched object has the same ID in the two returned catalogues, allowing for further comparisons between matched objects.

This method takes the following optional named arguments:

cat1magtype - The magnitude type to use for the first supplied catalogue. If not defined, will default to 'mag'. This is used for Astro::Catalog::Item objects that have fluxes that are not standard magnitudes (for example, one might set this to 'mag_iso' for magnitudes that come from the MAG_ISO column of a SExtractor catalogue).
cat2magtype - As for cat1magtype, but for the second supplied catalogue.
keeptemps - If this argument is set to true (1), then this method will keep temporary files used in processing. Defaults to false.
messages - no effect.
temp - Set the directory to hold temporary files. If not set, then a new temporary directory will be created using File::Temp.
timeout - Set the time in seconds to wait for the CCDPACK monolith to time out. Defaults to 60 seconds.
verbose - If this argument is set to true (1), then this method will print progress statements. Defaults to false.

This method usees the RIT Match application. In order for this method to work it must be able to find the match binary. It looks in the directory pointed to by the MATCH_DIR environment variable, and if that fails, looks through your $PATH. If it cannot be found, this method will croak.

Private Methods


match v0.09 and above had a requirement (or strong suggestion) that coordinate values be less than about 5000. Testing has shown that this limit is closer to about 1000, so this method looks at all of the coordinate values in the two catalogues and determines a scaling factor to bring those coordinate values under 1000.

  my $factor = _determine_scaling_factor( $cat1, $cat2 );






Brad Cavanagh <>


Copyright (C) 2006 Particle Physics and Astronomy Research Council. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place,Suite 330, Boston, MA 02111-1307, USA

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