uk.ac.starlink.table.join
Class HTMMatchEngine
java.lang.Object
|
+--uk.ac.starlink.table.join.SkyMatchEngine
|
+--uk.ac.starlink.table.join.HTMMatchEngine
- All Implemented Interfaces:
- MatchEngine
- public class HTMMatchEngine
- extends SkyMatchEngine
Implements the object matching interface for sky coordinates
using the HTM (Hierarchical Triangular Mesh) pixel-indexing scheme.
Note that the HEALPixMatchEngine
implementation normally gives
much faster matching than this and should generally be used in
preference.
- See Also:
- http://www.sdss.jhu.edu/htm/doc
Field Summary |
static double |
MESH_SCALE
Scaling factor which determines the size of the mesh cells used
as a multiple of the size of the separation. |
Constructor Summary |
HTMMatchEngine(double separation,
boolean useErrors)
Constructs a new match engine which considers two points
(RA,Dec tuples) to match if they are within a given angular
distance on the celestial sphere. |
Method Summary |
Object[] |
getBins(double ra,
double dec,
double err)
Returns all the HTM cells which fall wholly or partially within
err radians of a given position. |
void |
setSeparation(double separation)
Configures this match engine to consider two points
(RA,Dec tuples) to match if they are within a given angular
distance on the celestial sphere. |
Methods inherited from class uk.ac.starlink.table.join.SkyMatchEngine |
calculateSeparation, canBoundMatch, getBins, getMatchBounds, getMatchParameters, getMatchScoreInfo, getSeparation, getTupleInfos, getUseErrors, matchScore, setUseErrors, toString |
MESH_SCALE
public static final double MESH_SCALE
- Scaling factor which determines the size of the mesh cells used
as a multiple of the size of the separation. It can be used as
a tuning parameter. It must be >1.
- See Also:
- Constant Field Values
HTMMatchEngine
public HTMMatchEngine(double separation,
boolean useErrors)
- Constructs a new match engine which considers two points
(RA,Dec tuples) to match if they are within a given angular
distance on the celestial sphere.
- Parameters:
separation
- match radius in radiansuseErrors
- if true, per-row errors can be specified as
a third element of the tuples; otherwise only the fixed
separation value counts
setSeparation
public void setSeparation(double separation)
- Description copied from class:
SkyMatchEngine
- Configures this match engine to consider two points
(RA,Dec tuples) to match if they are within a given angular
distance on the celestial sphere.
- Overrides:
setSeparation
in class SkyMatchEngine
- Parameters:
separation
- match radius in radians
getBins
public Object[] getBins(double ra,
double dec,
double err)
- Returns all the HTM cells which fall wholly or partially within
err radians of a given position.
- Specified by:
getBins
in class SkyMatchEngine
- Parameters:
ra
- right ascensiondec
- declinationerr
- error
- Returns:
- bin list
- See Also:
SkyMatchEngine.getBins(java.lang.Object[])