Returns the minimum convex geometry that encloses all geometries within a raster.
Syntax
geometry ST_ConvexHull(raster source);
geometry ST_ConvexHull(raster source, integer pyramid);Parameters
| Parameter | Description |
|---|---|
| source | The raster object whose convex hull you want to compute. |
| pyramid | The pyramid level of the raster. Valid values start from 0. Default value: 0. |
Description
ST_ConvexHull returns the minimum convex geometry that encloses all geometries within a raster.
Examples
Basic usage — no pyramid level specified:
SELECT st_astext(st_convexhull(rast_object))
FROM raster_table;
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POLYGON((-180 90,180 90,180 -90,-180 -90,-180 90))Specify the pyramid level:
SELECT st_astext(st_convexhull(rast_object, 1))
FROM raster_table;
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POLYGON((-180 90,180 90,180 -90,-180 -90,-180 90))