ST_Contour
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Name

ST_Contour — Generates a set of vector contours from the provided raster band, using the GDAL contouring algorithm.

Synopsis

setof record ST_Contour(raster rast, integer bandnumber, double precision level_interval, double precision level_base, double precision[] fixed_levels, boolean polygonize);

Description

Generates a set of vector contours from the provided raster band, using the GDAL contouring algorithm.

When the fixed_levels parameter is a non-empty array, the level_interval and level_base parameters are ignored.

The polygonize parameter currently has no effect. Use the ST_Polygonize function to convert contours into polygons.

Return values are a set of records with the following attributes:

geom

The geometry of the contour line.

id

A unique identifier given to the contour line by GDAL.

value

The raster value the line represents. For an elevation DEM input, this would be the elevation of the output contour.

Availability: 3.2.0

Example

WITH c AS (
SELECT (ST_Contour(rast, 1, fixed_levels => ARRAY[100.0, 200.0, 300.0])).*
FROM dem_grid WHERE rid = 1
)
SELECT st_astext(geom), id, value
FROM c;

See Also

ST_InterpolateRaster

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