Class SkyPixer

java.lang.Object
uk.ac.starlink.ttools.plot2.layer.SkyPixer

public class SkyPixer extends Object
Maps positions on the unit sphere to pixel indices using a given pixel scheme. The current implementation uses the HEALPix nested scheme for a given HEALPix level.

Instances of this class are not in general thread-safe.

Since:
20 Sep 2015
Author:
Mark Taylor
  • Constructor Summary

    Constructors
    Constructor
    Description
    SkyPixer(int level)
    Constructor.
  • Method Summary

    Modifier and Type
    Method
    Description
    long
    getIndex(double[] v3)
    Returns the sky pixel index corresponding to a given position on the unit sphere.
    int
    Returns the HEALPix level for this pixellisation scheme.
    long
    Returns the number of pixels used by this pixellisation scheme.
    boolean
    Indicates whether this object uses the HEALPix NESTED or RING scheme.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Constructor Details

    • SkyPixer

      public SkyPixer(int level)
      Constructor.
      Parameters:
      level - HEALPix level
  • Method Details

    • getLevel

      public int getLevel()
      Returns the HEALPix level for this pixellisation scheme.
      Returns:
      HEALPix level
    • getPixelCount

      public long getPixelCount()
      Returns the number of pixels used by this pixellisation scheme.
      Returns:
      pixel count
    • getIndex

      public long getIndex(double[] v3)
      Returns the sky pixel index corresponding to a given position on the unit sphere.
      Parameters:
      v3 - 3-element vector giving a position on the celestial sphere; if the modulus of the vector is not close to unity, the result is undefined
      Returns:
      pixel index
    • isNested

      public boolean isNested()
      Indicates whether this object uses the HEALPix NESTED or RING scheme.
      Returns:
      true for nested, false for ring; currently always true