uk.ac.starlink.ttools.cone
Class HealpixTiling

java.lang.Object
  extended by uk.ac.starlink.ttools.cone.HealpixTiling
All Implemented Interfaces:
SkyTiling

public class HealpixTiling
extends Object
implements SkyTiling

Tiling implementation based on the HEALPix scheme.

Since:
12 Dec 2007
Author:
Mark Taylor

Constructor Summary
HealpixTiling(int k, boolean nest)
          Constructor.
 
Method Summary
 long getPositionTile(double ra, double dec)
          Returns the index of the tile in which a given sky position falls.
 long[] getTileRange(double ra, double dec, double radius)
          Returns the bounds of a range of pixels which is known to cover a given cone on the sky.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

HealpixTiling

public HealpixTiling(int k,
                     boolean nest)
Constructor.

Parameters:
k - log to base 2 of HEALPix Nside parameter
nest - true for nesting scheme, false for ring scheme
Method Detail

getPositionTile

public long getPositionTile(double ra,
                            double dec)
Description copied from interface: SkyTiling
Returns the index of the tile in which a given sky position falls.

Specified by:
getPositionTile in interface SkyTiling
Parameters:
ra - right ascension in degrees
dec - declination in degrees
Returns:
tile index for position

getTileRange

public long[] getTileRange(double ra,
                           double dec,
                           double radius)
Description copied from interface: SkyTiling
Returns the bounds of a range of pixels which is known to cover a given cone on the sky. The return value is a two-element array, (lo,hi). Every point in the specified cone must have a tile index which is greater than or equal to the first element of that array, and less than or equal to the second element. If the question cannot be answered, or if the range is thought to be too large to be of use (for instance, if it would take a long time to calculate), then null may be returned.

Specified by:
getTileRange in interface SkyTiling
Parameters:
ra - right ascension in degrees
dec - declination in degrees
radius - radius in degrees
Returns:
2-element array giving inclusive (low, high) bounds of tile range covering the cone


Copyright © 2015 Central Laboratory of the Research Councils. All Rights Reserved.