ST_CreateOverview — Create an reduced resolution version of a given raster coverage.
regclass ST_CreateOverview(regclass tab, name col, int factor, text algo='NearestNeighbor'
Create an overview table with resampled tiles from the source table.
Output tiles will have the same size of input tiles and cover the same
spatial extent with a lower resolution (pixel size will be
factor of the original in both directions).
The overview table will be made available in the
raster_overviews catalog and will have raster
Algorithm options are: 'NearestNeighbor', 'Bilinear', 'Cubic', 'CubicSpline', and 'Lanczos'. Refer to: GDAL Warp resampling methods for more details.
Output to generally better quality but slower to product format
SELECT ST_CreateOverview('mydata.mytable'::regclass, 'rast', 2, 'Lanczos');
Output to faster to process default nearest neighbor
SELECT ST_CreateOverview('mydata.mytable'::regclass, 'rast', 2);