Cross Matching

Overview

Cross Matching is the task of finding records from different astronomy catalogues that refer to the same source object based on spatial co-location. This is a costly operation to solve especially for large datasets of up to a billion records each.

Our algorithm applies the filter-refine strategy used in spatial database systems and plane sweep techniques from computational geometry. Assessment on sample catalogues indicate that the algorithm performs at least an order of magnitude better than the techniques in current use.

The software is available for download.

Plane Sweep Algorithm

Two demonstrations explaining how the plane sweep alogorithm is used for catalogue cross matching and finding nearest neighbours are provided below.

Cross Macthing

Finding Nearest Neighbours

Reports

"Large Catalogue Query Performance in Relational Databases"
R. Power.
Publications of the Astronomical Society of Australia (PASA) Volume 24 Number 1, 2007, pp 13-20.

"An O(NlogM) Algorithm for Catalogue Crossmatching"
D. Devereux, D. Abel, R. Power, P. Lamb
Astronomical Data Analysis Software and Systems (ADASS) XIV, ASP Conference Series 347, 2005, pp 346-349. Editors: P. Shopbell, M. Britton, and R, Ebert