Building pyramids on a raster value in an ST_Raster column
Pyramids can be constructed on a raster value stored in an ST_Raster column by updating the value with the buildPyramid function.
The buildPyramid function builds reduced-resolution pyramids on the specified ST_Raster value. Reduced-resolution pyramids are necessary to provide a consistent pixel data return rate as the application zooms in and out of a map containing rasters.
- Use a SQL UPDATE statement with the ST_Raster buildPyramid function to create pyramids on ST_Raster values on specific records in a table.
The following examples for each of the supported database management systems show a bilinear pyramid being built on the rasters in the table urban_area for all records with the name all_cities:
UPDATE URBAN_AREA t SET raster = t.raster.buildPyramid('bilinear') WHERE NAME = 'ALL_CITIES';
UPDATE urban_area SET raster = buildPyramid(raster,'bilinear') WHERE name = 'all_cities';
UPDATE urban_area SET raster = raster.buildPyramid('bilinear') WHERE name = 'all_cities';