Package uk.ac.starlink.table.join

Class HtmSkyPixellator

java.lang.Object
uk.ac.starlink.table.join.HtmSkyPixellator
All Implemented Interfaces:
SkyPixellator
public class HtmSkyPixellator extends Object implements SkyPixellator
Implements sky pixellisation using the HTM (Hierarchical Triangular Mesh) indexing scheme.

Note that the HealpixSkyPixellator implementation normally gives much faster matching than this and should generally be used in preference.

Author:
Mark Taylor (Starlink)
See Also:

  • Constructor Details

    • HtmSkyPixellator

      public HtmSkyPixellator()
      Constructor.

  • Method Details

    • setScale

      public void setScale(double scale)
      Description copied from interface: SkyPixellator
      Sets the characteristic angular scale for this pixellator. Pixels should be approximately the size given, so that a larger scale corresponds to larger pixel sizes. The details of pixel size are determined by the details of the pixellation scheme however.
      Specified by:
      setScale in interface SkyPixellator
      Parameters:
      scale - pixel length scale in radians

    • getScale

      public double getScale()
      Description copied from interface: SkyPixellator
      Returns the most recently set angular scale.
      Specified by:
      getScale in interface SkyPixellator
      Returns:
      pixel length scale in radians

    • getTuningParameter

      public uk.ac.starlink.table.DescribedValue getTuningParameter()
      Description copied from interface: SkyPixellator
      Returns a parameter whose value may be adjusted to alter the pixellisation scale. This is not necessarily the same as the scale attribute (its value need not be an angle).
      Specified by:
      getTuningParameter in interface SkyPixellator
      Returns:
      tuning parameter

    • createVariableRadiusPixerFactory

      public Supplier<VariableRadiusConePixer> createVariableRadiusPixerFactory()
      Description copied from interface: SkyPixellator
      Returns a factory for variable radius pixel calculators based on the current settings of this object.
      Specified by:
      createVariableRadiusPixerFactory in interface SkyPixellator
      Returns:
      immutable factory for pixel calculators; subsequent changes to this object will not affect the objects it supplies

    • createFixedRadiusPixerFactory

      public Supplier<FixedRadiusConePixer> createFixedRadiusPixerFactory(double radius)
      Description copied from interface: SkyPixellator
      Returns a factory for fixed radius pixel calculators based on the current settings of this object.
      Specified by:
      createFixedRadiusPixerFactory in interface SkyPixellator
      Parameters:
      radius - cone radius in radians
      Returns:
      immutable factory for pixel calculators; subsequent changes to this object will not affect the objects it supplies

    • setLevel

      public void setLevel(int level)
      Sets the HTM level value, which determines sky pixel size. May be in the range 0 (90deg) to 24 (0.01"). If set to -1, a suitable value will be used based on the scale.
      Parameters:
      level - new level value

    • getLevel

      public int getLevel()
      Returns the HTM level, which determines sky pixel size. The returned value may be the result of a default determination based on scale if no explicit level has been set hitherto, and a non-zero scale is available.
      Returns:
      level level value used by this engine

    • calculateDefaultLevel

      public int calculateDefaultLevel(double scale)
      Determines a default value to use for the level paramer based on a given scale.
      Parameters:
      scale - sky distance scale angle, in radians