# Matching catalogues using Groth method

A Pattern-Matching Algorithm for Two-Dimensional Coordinate Lists Eduard J. Groth 1986 AJ 19, 5

http://adsabs.harvard.edu/abs/1986AJ.....91.1244G

Gmatch is released under the GPL (version 3 or any later version)

## Sample usage

>>> from gmatch import gmatch >>> # load cat1 and cat2 from somewhere >>> # they are numpy arrays >>> # N rows, 2 columns >>> cat1.shape (20, 2) >>> cat2.shape (20, 2) >>> matches = gmatch(cat1, cat2, eps=1e-3) >>> # eps is the *relative* tolerance in xy >>> matches None >>> # if the return value is None, the catalogues >>> # do not match>>> from gmatch import gmatch >>> # load cat1 and cat2 from somewhere >>> # they are numpy arrays >>> matches = gmatch(cat1, cat2, eps=1e-3) >>> # eps is the *relative* tolerance in xy >>> if matches: ... matches[0] ... matches[1] >>> # if the return value is not None >>> # then is a tuple >>> # first element matched objects in cat1 >>> # second element matched objects in cat2