CDS xMatch service documentation: Cross-match area

2.2 Cross-match area

All-sky

$\includegraphics[width=\textwidth ]{img/algoAllSky.png}$

All sources of the catalogue A are cross-matched.

Cone

$\includegraphics[width=\textwidth ]{img/algoCone.png}$

Only the sources of the catalogue A lying at an angular distance less than Radius from the given position (Center) are cross-matched.

Healpix Cell

$\includegraphics[width=\textwidth ]{img/algoHealpix.png}$

Only the sources of the catalogue A which are inside the HEALPix pixel of given Index and Nside are cross-matched. The given Index is the index defined by the HEALPix Nested scheme in the ICRS frame. For more information on HEALPix, see http://healpix.jpl.nasa.gov or Górski et al. (2005).