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### B.1.6 Tilings

Pixel tiling functions for the celestial sphere.

htmIndex( level, ra, dec )
  Gives the HTM (Hierachical Triangular Mesh) pixel index for a given sky position.
healpixNestIndex( k, ra, dec )
  Gives the pixel index for a given sky position in the HEALPix NEST scheme.
healpixRingIndex( k, ra, dec )
  Gives the pixel index for a given sky position in the HEALPix RING scheme.
healpixK( pixelsize )
  Gives the HEALPix resolution parameter suitable for a given pixel size. This `k` value is the logarithm to base 2 of the Nside parameter.
healpixResolution( k )
  Gives the approximate resolution in degrees for a given HEALPix resolution parameter `k` This `k` value is the logarithm to base 2 of the Nside parameter.
htmLevel( pixelsize )
  Gives the HTM `level` parameter suitable for a given pixel size.
htmResolution( level )
  Gives the approximate resolution in degrees for a given HTM depth level.

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TOPCAT - Tool for OPerations on Catalogues And Tables
Starlink User Note253
TOPCAT web page: http://www.starlink.ac.uk/topcat/
Author email: m.b.taylor@bristol.ac.uk
Mailing list: topcat-user@bristol.ac.uk