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:

http://www.skyserver.org/htm/doc/java/index.html

Constructor Summary

Constructors

Constructor and Description
HtmSkyPixellator() Constructor.

Method Summary

Modifier and Type	Method and Description
int	calculateDefaultLevel(double scale) Determines a default value to use for the level paramer based on a given scale.
java.util.function.Supplier<FixedRadiusConePixer>	createFixedRadiusPixerFactory(double radius) Returns a factory for fixed radius pixel calculators based on the current settings of this object.
java.util.function.Supplier<VariableRadiusConePixer>	createVariableRadiusPixerFactory() 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.
DescribedValue	getTuningParameter() 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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HtmSkyPixellator

public HtmSkyPixellator()

Constructor.

Method Detail

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 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 java.util.function.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 java.util.function.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