Package uk.ac.starlink.table.join
Interface SkyPixellator
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- All Known Implementing Classes:
HealpixSkyPixellator
,HtmSkyPixellator
,PixtoolsHealpixSkyPixellator
public interface SkyPixellator
Provides a pixellisation of the celestial sphere. Usually it is necessary to callsetScale(double)
before an instance of this class can be used.- Since:
- 5 Sep 2011
- Author:
- Mark Taylor
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description java.lang.Object[]
getPixels(double alpha, double delta, double radius)
Returns an array of objects representing pixels in a given region.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
setScale(double scale)
Sets the characteristic angular scale for this pixellator.
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Method Detail
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setScale
void setScale(double scale)
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.- Parameters:
scale
- pixel length scale in radians
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getScale
double getScale()
Returns the most recently set angular scale.- Returns:
- pixel length scale in radians
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getPixels
java.lang.Object[] getPixels(double alpha, double delta, double radius)
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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getTuningParameter
DescribedValue getTuningParameter()
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).- Returns:
- tuning parameter
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