30.8 SDO_SAM.SPATIAL_CLUSTERS
Format
SDO_SAM.SPATIAL_CLUSTERS( tablename IN VARCHAR2, colname IN VARCHAR2, max_clusters IN NUMBER, allow_outliers IN VARCHAR2 DEFAULT 'TRUE', tablepartition IN VARCHAR2 DEFAULT NULL ) RETURN SDO_REGIONSET;
Description
Computes clusters using the existing R-tree index, and returns a set of SDO_REGION objects where the geometry column specifies the boundary of each cluster and the geometry_key
value is set to null.
Parameters
- tablename
-
Name of the data mining table.
- colname
-
Name of the column in
tablename
that holds the location coordinates. - max_clusters
-
Maximum number of clusters to obtain.
- allow_outliers
-
TRUE
(the default) causes outlying values (isolated instances) to be included in the spatial clusters;FALSE
causes outlying values not to be included in the spatial clusters. (TRUE
accommodates all data and may result in larger clusters;FALSE
may exclude some data and may result in smaller clusters.) - tablepartition
-
Name of the partition in
tablename
.
Usage Notes
The clusters are computed using the spatial R-tree index on tablename
.
Examples
The following example clusters the locations in cities into at most three clusters, and includes outlying values in the clusters.
SELECT * FROM TABLE(sdo_sam.spatial_clusters('PROJ_CITIES', 'LOCATION', 3, 'TRUE'));
Parent topic: SDO_SAM Package (Spatial Analysis and Mining)