Class SkyPixer
java.lang.Object
uk.ac.starlink.ttools.plot2.layer.SkyPixer
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
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionlong
getIndex
(double[] v3) Returns the sky pixel index corresponding to a given position on the unit sphere.int
getLevel()
Returns the HEALPix level for this pixellisation scheme.long
Returns the number of pixels used by this pixellisation scheme.boolean
isNested()
Indicates whether this object uses the HEALPix NESTED or RING scheme.
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Constructor Details
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SkyPixer
public SkyPixer(int level) Constructor.- Parameters:
level
- HEALPix level
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Method Details
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getLevel
public int getLevel()Returns the HEALPix level for this pixellisation scheme.- Returns:
- HEALPix level
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getPixelCount
public long getPixelCount()Returns the number of pixels used by this pixellisation scheme.- Returns:
- pixel count
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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
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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
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