9.4 SDO_GEOR_AGGR.getMosaicStatistics

Format

SDO_GEOR_AGGR.getMosaicStatistics(
     inGeoRasters   IN SYS_REFCURSOR, 
     skipFactor     IN NUMBER DEFAULT 1, 
     genHistogram   IN VARCHAR2 DEFAULT 'FALSE', 
     outStatistics  OUT SDO_NUMBER_ARRAYSET, 
     outHistograms  OUT SDO_GEOR_HISTOGRAM_ARRAY);

or

SDO_GEOR_AGGR.getMosaicStatistics(
     georasterTableNames  IN VARCHAR2, 
     georasterColumnNames IN VARCHAR2, 
     skipFactor           IN NUMBER DEFAULT 1, 
     genHistogram         IN VARCHAR2 DEFAULT 'FALSE', 
     outStatistics        OUT SDO_NUMBER_ARRAYSET, 
     outHistograms        OUT SDO_GEOR_HISTOGRAM_ARRAY);

Description

Calculates and returns the estimated statistics of a virtual mosaic or a collection of GeoRaster objects.

Parameters

inGeoRasters

Source GeoRaster objects in a cursor.

georasterTableNames

Names (comma-separated) of the tables containing the source GeoRaster objects.

georasterColumnNames

Names (comma-separated) of the columns of type SDO_GEORASTER in tables corresponding to the table names in georasterTableNames.

skipFactor

Number indicating every nth image to be used during the calculation. For example, if skipFactor is 3, then every third image in the source images is used in the statistics calculation. The skipFactor parameter can be used to reduce the calculation time for a large image set. The default is 1 (that is, every image is used; no images are skipped).

genHistogram

String (true or false) whether to return the estimated histogram of the virtual mosaic. The default is false.

outStatistics

The returned statistics in the order of the bands of the source images. For each band, if genHistogram is false, the statistics that are returned are min, max, mean, and std; but if genHistogram is true, the statistics that are returned are min, max, mean, std, median, and mode.

For example, if the source images have three bands and

• if genHistogram is false, the ourStatistics parameter has the value: sdo_number_arrayset(sdo_number_array(17.0, 255.0, 154.64, 71.29), sdo_number_array(14.0, 255.0, 155.86, 56.08), sdo_number_array(0.0, 255.0, 98.60, 73.08))

• if genHistogram is true, the ourStatistics parameter has the value: sdo_number_arrayset(sdo_number_array(17.0, 255.0, 154.64, 71.29, 112.0, 255.0), sdo_number_array(14.0, 255.0, 155.86, 56.08, 143.0, 255.0), sdo_number_array(0.0, 255.0, 98.60, 73.08, 61.0, 0.0))

The SDO_NUMBER_ARRAYSET type is defined as VARRAY(1048576) OF SDO_NUMBER_ARRAY.

outHistograms

If genHistogram is the string true, outHistograms will contain the returned histograms as an array of type SDO_GEOR_HISTOGRAM_ARRAY Collection Type, with each item containing the histogram for each band.

If genHistogram is the string false, outHistograms will be null.

Usage Notes

To calculate the statistics of the source images, the statistics of the source images must be present in the GeoRaster object's metadata.

The source images must have the same number of bands and same celldepth.

The returned statistics for non-overlapping source images with celldepth less than or equal to 16bit are accurate calculations; otherwise, the returned statistics are close estimates.

Examples

The following example shows how to get the statistics when the virtual mosaic or the collection of GeoRaster objects is a cursor. The skipFactor is 1 and genHistogram parameter is false.

declare
    cur sys_refcursor,
    outStats sdo_number_arrayset := null;
    outHists sdo_geor_histogram_array := null;
begin
     open cur for select georaster from georaster_table_1 union all select georaster from georaster_table_2;
     sdo_geor_aggr.getMosaicStatistics(cur, 1, 'false', outStats, outHists);
     close cur;
end;
/

The following example shows how to get the statistics by specifying the table column names. The skipFactor is 5 and genHistogram parameter is true.

declare
    outStats sdo_number_arrayset := null;
    outHists sdo_geor_histogram_array := null;
begin
     sdo_geor_aggr.getMosaicStatistics('georaster_table_1, georaster_table_2', 'georaster, georaster', 5, 'true', outStats, outHists);
end;
/