Package uk.ac.starlink.table.join
Class PixtoolsHealpixSkyPixellator
- java.lang.Object
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- uk.ac.starlink.table.join.HealpixSkyPixellator
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- uk.ac.starlink.table.join.PixtoolsHealpixSkyPixellator
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- All Implemented Interfaces:
SkyPixellator
public class PixtoolsHealpixSkyPixellator extends HealpixSkyPixellator
HEALPix sky pixellator using the PixTools library. This implementation is based on the PixTools Java HEALPix classes written by Nickolai Kouropatkine at Fermilab. The maximum K value is 20.- Author:
- Mark Taylor (Starlink), Nickolai Kouropatkine (EAG, Fermilab)
- See Also:
- http://home.fnal.gov/~kuropat/HEALPIX/PixTools.html
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Constructor Summary
Constructors Constructor Description PixtoolsHealpixSkyPixellator()
Constructs a pixellator using the default scheme (RING).PixtoolsHealpixSkyPixellator(boolean nested)
Constructs a pixellator using either the RING or NESTED HEALPix scheme.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
calculateDefaultK(double scale)
Determines a default value to use for the HEALPix k parameter based on a given scale.protected void
configureK(int k)
Updates internal state for the current value of the k parameter.java.lang.Object[]
getPixels(double alpha, double delta, double radius)
Returns an array of objects representing pixels in a given region.-
Methods inherited from class uk.ac.starlink.table.join.HealpixSkyPixellator
getHealpixK, getMaxK, getScale, getTuningParameter, setHealpixK, setScale
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Constructor Detail
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PixtoolsHealpixSkyPixellator
public PixtoolsHealpixSkyPixellator(boolean nested)
Constructs a pixellator using either the RING or NESTED HEALPix scheme.- Parameters:
nested
- false for RING scheme, true for NESTED
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PixtoolsHealpixSkyPixellator
public PixtoolsHealpixSkyPixellator()
Constructs a pixellator using the default scheme (RING).
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Method Detail
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getPixels
public java.lang.Object[] getPixels(double alpha, double delta, double radius)
Description copied from interface:SkyPixellator
Returns an array of objects representing pixels in a given region. The parameters specify a small circle on the sphere; any pixels which overlap this circle must be returned (additional pixels may also be returned). The output objects are of some opaque type, but must implement theequals
andhashCode
methods appropriately, so that objects returned from one call can be compared for identity with objects returned from a subsequent call. This comparability is only guaranteed to work if the pixel scale is not changed in between calls.- Parameters:
alpha
- right ascension of circle centre in radiansdelta
- declination of circle centre in radiansradius
- radius of circle in radians- Returns:
- array of opaque but comparable pixel objects
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configureK
protected void configureK(int k)
Description copied from class:HealpixSkyPixellator
Updates internal state for the current value of the k parameter.- Specified by:
configureK
in classHealpixSkyPixellator
- Parameters:
k
- HEALPix order
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calculateDefaultK
public int calculateDefaultK(double scale)
Determines a default value to use for the HEALPix k parameter based on a given scale.- Specified by:
calculateDefaultK
in classHealpixSkyPixellator
- Parameters:
scale
- distance scale, in radians
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