Format
SDO_SAM.TILED_AGGREGATES(
theme_name IN VARCHAR2,
theme_colname IN VARCHAR2,
aggr_type_string IN VARCHAR2,
aggr_col_string IN VARCHAR2,
tiling_level IN NUMBER DEFAULT NULL,
tiling_domain IN SDO_DIM_ARRAY DEFAULT NULL,
zero_agg_tiles IN NUMBER DEFAULT 0,
xdivs IN NUMBER DEFAULT NULL,
ydivs IN NUMBER DEFAULT NULL
) RETURN SDO_REGAGGRSET;Description
Tiles aggregates for a ___domain. For each tile, computes the intersecting geometries from the theme table; the values in the aggr_col_string column are weighted proportionally to the area of the intersection, and aggregated according to aggr_col_string.
Parameters
Table containing theme information (for example, demographic information).
Name of the column in the theme_name table that contains geometry objects.
Any Oracle SQL aggregate function that accepts one or more numeric values and computes a numeric value, such as SUM, MIN, MAX, or AVG.
Name of a column in the theme_name table on which to compute aggregate values. An example might be a POPULATION column.
Level to be used to create tiles. If you specify this parameter, the extent of each dimension is divided into 2^tiling_level parts, resulting in at most 4*tiling_level tiles. (Specify either this parameter or the combination of the xdivs and ydivs parameters.)
Domain for the tiling level. The parameter is not required, and if you do not specify it, the extent associated with the theme_name table is used.
Specify 0 to exclude tiles that have a value of 0 for the computed aggregate, or specify 1 to return all tiles. The default value is 0, which ensures that only tiles with a nonzero aggregate value are returned.
The number of times that the extent in the first dimension is divided, such that the total number of parts is xdivs + 1. For example, if you specify 10 for xdivs, the extent of the first dimension is divided into 11 parts.
The number of times that the extent in the second dimension is divided, such that the total number of parts is ydivs + 1. For example, if you specify 10 for ydivs, the extent of the second dimension is divided into 11 parts.
Usage Notes
This function is similar to SDO_SAM.AGGREGATES_FOR_LAYER, but the results are dynamically generated using tiling information. Given a theme_name table, the tiling ___domain is determined. Based on the tiling_level value or the xdivs and ydivs values, the necessary tiles are generated. For each tile geometry, thematic aggregates are computed as described in the Usage Notes for SDO_SAM.AGGREGATES_FOR_LAYER.
You must specify either the tiling_level parameter or both the xdivs and ydivs parameters. If you specify all three of these parameters, the tiling_level parameter is ignored and the xdivs and ydivs parameters are used.
If you specify the xdivs and ydivs parameters, the total number of grids (tiles) returned is (xdivs+1)*(ydivs+1).
This function returns an object of type SDO_REGAGGRSET. The SDO_REGAGGRSET object type is defined as:
TABLE OF SDO_REGAGGR
The SDO_REGAGGR object type is defined as:
Name Null? Type ----------------------------------------- -------- ---------------------------- REGION_ID VARCHAR2(24) GEOMETRY MDSYS.SDO_GEOMETRY AGGREGATE_VALUE NUMBER
Examples
The following example computes the sum of the population rows of POLY_4PT_TEMP table intersecting with each tile. The extent of the POLY_4PT_TEMP table stored in the USER_SDO_GEOM_METADATA view is used as the ___domain, and a tiling level of 2 is used (that is, the ___domain is divided into 16 tiles).
SELECT a.geometry, a.aggregate_value
from TABLE(sdo_sam.tiled_aggregates('POLY_4PT_TEMP',
'GEOMETRY', 'SUM', 'POPULATION', 2)) a;
GEOMETRY(SDO_GTYPE, SDO_SRID, SDO_POINT(X, Y, Z), SDO_ELEM_INFO, SDO_ORDINATES)
--------------------------------------------------------------------------------
AGGREGATE_VALUE
---------------
SDO_GEOMETRY(2003, 8307, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 3), SDO_ORDINATE_ARR
AY(-180, -90, -90, -45))
.007150754
SDO_GEOMETRY(2003, 8307, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 3), SDO_ORDINATE_ARR
AY(-180, -45, -90, 0))
.034831005
SDO_GEOMETRY(2003, 8307, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 3), SDO_ORDINATE_ARR
AY(-180, 0, -90, 45))
7.73307783
SDO_GEOMETRY(2003, 8307, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 3), SDO_ORDINATE_ARR
AY(-90, -90, 0, -45))
.019498368
SDO_GEOMETRY(2003, 8307, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 3), SDO_ORDINATE_ARR
AY(-90, -45, 0, 0))
.939061456
SDO_GEOMETRY(2003, 8307, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 3), SDO_ORDINATE_ARR
AY(-90, 0, 0, 45))
1.26691592
SDO_GEOMETRY(2003, 8307, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 3), SDO_ORDINATE_ARR
AY(0, 0, 90, 45))
40
7 rows selected.