This topic describes the ST_AddZ function. This function specifies the Z coordinate of a geometry based on the band of the raster that is converted from the geometry.
Syntax
geometry ST_AddZ(raster source,
geometry geom,
integer pyramid,
integer band);Parameters
| Parameter | Description |
|---|---|
| source | The raster from which the geometry is converted. |
| geom | The geometry whose Z coordinate you want to specify. |
| pyramid | The pyramid level of the raster. Valid values start from 0. If the number of layers in the pyramid is N, the value of this parameter is an integer that ranges from 0 to the difference between N and 1. Default value: 0. |
| band | The band of the raster. Valid values start from 0. If the number of bands of the raster is N, the value of this parameter is an integer that ranges from 0 to the difference between N and 1. Default value: 0. |
Description
This function specifies the Z coordinate of a geometry based on the band of the raster that is converted from the geometry. If the raster is georeferenced, this function returns a geographic coordinate of the geometry. If the raster is not georeferenced, this function returns a pixel coordinate of the geometry.
Note All of the points on the geometry must fall within the raster.
Examples
SELECT ST_AddZ(rast_object, ST_GeomFromText('POINT(120.5 30.6)', 4326), 0, 0)
FROM raster_table;
------------------------
POINT Z(120.5 30.6 27)
SELECT ST_AddZ(rast_object, ST_GeomFromText('POINT(120.5 30.6)', 4326), 1, 1)
FROM raster_table;
------------------------
POINT Z(120.5 30.6 115)