ST_Contour

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=1, double precision level_interval=100.0, double precision level_base=0.0, double precision[] fixed_levels=ARRAY[], boolean polygonize=false);

Beschreibung

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.

Input parameters are:

rast: The raster to generate the contour of
bandnumber: The band to generate the contour of
level_interval: The elevation interval between contours generated
level_base: The "base" relative to which contour intervals are applied, this is normally zero, but could be different. To generate 10m contours at 5, 15, 25, ... the LEVEL_BASE would be 5.
fixed_levels: The elevation interval between contours generated
polygonize: If true, contour polygons will be created, rather than polygon lines.

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

Beispiel

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;

Siehe auch

ST_InterpolateRaster