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.
- See Also:
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)
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(Object[] radec)
Returns all the HTM cells which fall wholly or partially within
separation 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. |
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)
- 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 radians
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(Object[] radec)
- Returns all the HTM cells which fall wholly or partially within
separation radians of a given position.
- Parameters:
radec
- 2-element array of Number objects giving RA & Dec
of the position to test
- Returns:
- set of bin keys which might be returned by invoking this
method on other tuples which count as matches for the
submitted tuple