This topic describes the ST_Extent function, which obtains the coordinate range of
a raster in the following format: '((maxX,maxY),(minX,minY))'.
Syntax
BOX ST_Extent(raster raster_obj,CoorSpatialOption csOption = 'WorldFirst')
BOX ST_Extent(raster raster_obj, integer pyramid, CoorSpatialOption csOption = 'WorldFirst')Parameters
| Parameter | Description |
|---|---|
| raster_obj | The raster whose coordinate range you want to obtain. |
| csOption | The type of coordinate to return. |
| pyramid | The pyramid level at which the raster resides. Valid values start from 0. |
Description
This function obtains the coordinate range of a raster based on the value of the csOption parameter:
- Raster: This function returns pixel coordinates.
- World: This function returns world coordinates.
- WorldFirst: This function preferentially returns world coordinates. If the raster is georeferenced, this function returns world coordinates. Otherwise, this function returns pixel coordinates.
Example
select ST_Extent(raster_obj, 'Raster'::CoorSpatialOption) from raster_table;
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((255, 255), (0, 0))