Package uk.ac.starlink.table.join
Class HtmSkyPixellator
java.lang.Object
uk.ac.starlink.table.join.HtmSkyPixellator
- All Implemented Interfaces:
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:
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint
calculateDefaultLevel
(double scale) Determines a default value to use for the level paramer based on a given scale.createFixedRadiusPixerFactory
(double radius) Returns a factory for fixed radius pixel calculators based on the current settings of this object.Returns a factory for variable radius pixel calculators based on the current settings of this object.int
getLevel()
Returns the HTM level, which determines sky pixel size.double
getScale()
Returns the most recently set angular scale.uk.ac.starlink.table.DescribedValue
Returns a parameter whose value may be adjusted to alter the pixellisation scale.void
setLevel
(int level) Sets the HTM level value, which determines sky pixel size.void
setScale
(double scale) Sets the characteristic angular scale for this pixellator.
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Constructor Details
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HtmSkyPixellator
public HtmSkyPixellator()Constructor.
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Method Details
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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 interfaceSkyPixellator
- Parameters:
scale
- pixel length scale in radians
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getScale
public double getScale()Description copied from interface:SkyPixellator
Returns the most recently set angular scale.- Specified by:
getScale
in interfaceSkyPixellator
- Returns:
- pixel length scale in radians
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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 interfaceSkyPixellator
- Returns:
- tuning parameter
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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 interfaceSkyPixellator
- Returns:
- immutable factory for pixel calculators; subsequent changes to this object will not affect the objects it supplies
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createFixedRadiusPixerFactory
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 interfaceSkyPixellator
- Parameters:
radius
- cone radius in radians- Returns:
- immutable factory for pixel calculators; subsequent changes to this object will not affect the objects it supplies
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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
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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
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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
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