matching catalogues

match_cat.py

from astropy import coordinates as coord
from astropy import units as u, constants as const
import pandas as pd
cats = ['ut150625_g.h5', 'ut150625_r.h5', 'ut150625_u.h5']

gdata = pd.read_hdf(cats[0], 'data')
gdata = gdata[gdata.type == 1]
gcat = coord.SkyCoord(gdata.RA.values, gdata.Dec.values, unit=u.degree)

rdata = pd.read_hdf(cats[1], 'data')
rdata = rdata[rdata.type == 1]
rcat = coord.SkyCoord(rdata.RA.values, rdata.Dec.values, unit=u.degree)

udata = pd.read_hdf(cats[2], 'data')
udata = udata[udata.type == 1]
ucat = coord.SkyCoord(udata.RA.values, udata.Dec.values, unit=u.degree)

rg_id, rg_dist, _ = rcat.match_to_catalog_sky(gcat)
ru_id, ru_dist, _ = rcat.match_to_catalog_sky(ucat)
close_match_filter = (rg_dist.to(u.arcsecond) < 0.1 * u.arcsecond) & (ru_dist.to(u.arcsecond) < 0.1 * u.arcsecond)

final_catalogue = pd.DataFrame(columns=['RA', 'Dec', 'r', 'r_err'], index=np.arange(np.sum(close_match_filter)))
final_catalogue['RA'] = rdata['RA'].values[close_match_filter]
final_catalogue['Dec'] = rdata['Dec'].values[close_match_filter]
final_catalogue['r'] = rdata['mag'].values[close_match_filter]
final_catalogue['r_err'] = rdata['dM'].values[close_match_filter]

final_catalogue['g'] = gdata['mag'].values[rg_id][close_match_filter]
final_catalogue['g_err'] = gdata['dM'].values[rg_id][close_match_filter]
final_catalogue['u'] = udata['mag'].values[ru_id][close_match_filter]
final_catalogue['u_err'] = udata['dM'].values[ru_id][close_match_filter]