RS_Clip¶

Introduction: Returns a raster that is clipped by the given geometry.

If crop is not specified then it will default to true, meaning it will make the resulting raster shrink to the geometry's extent and if noDataValue is not specified then the resulting raster will have the minimum possible value for the band pixel data type.

For polygon geometries, the allTouched parameter (Since v1.7.1) determines how pixels are selected:

When true, pixel selection also includes cells entered by the polygon's boundary, following the RS_AsRaster rules.
When false (default), pixels whose centroid intersects the polygon will be included.

A polygon never selects a pixel it touches only on the pixel's boundary, whichever edge that is. A polygon aligned with grid lines selects only pixels inside it.

Point geometries select the single pixel containing the point under the half-open rule, regardless of allTouched. Line rasterization follows the cells entered by its segments rather than requiring a pixel-centre intersection. A point or line lying on an internal grid edge selects the pixel after it in pixel order; one lying on the raster's last edge selects none. A neighboring pixel contacted only at a line endpoint is not selected unless the segment enters it.

For LineString geometries, allTouched can also change the rasterization window at grid boundaries and therefore the selected pixels.

Note

Since v1.5.1, if the coordinate reference system (CRS) of the input geom geometry differs from that of the raster, then geom will be transformed to match the CRS of the raster. If the raster or geom doesn't have a CRS then it will default to 4326/WGS84.
Since v1.7.0, RS_Clip function will return null if the raster and geometry geometry do not intersect. If you want to throw an exception in this case, you can set the lenient parameter to false.

RS_Clip

Format:

RS_Clip(raster: Raster, band: Integer, geom: Geometry)

RS_Clip(raster: Raster, band: Integer, geom: Geometry, allTouched: Boolean)

RS_Clip(raster: Raster, band: Integer, geom: Geometry, allTouched: Boolean, noDataValue: Double)

RS_Clip(raster: Raster, band: Integer, geom: Geometry, allTouched: Boolean, noDataValue: Double, crop: Boolean)

RS_Clip(raster: Raster, band: Integer, geom: Geometry, allTouched: Boolean, noDataValue: Double, crop: Boolean, lenient: Boolean)

Return type: Raster

Since: v1.5.1

SQL Example

SELECT RS_Clip(
        RS_FromGeoTiff(content), 1,
        ST_GeomFromWKT('POLYGON ((236722 4204770, 243900 4204770, 243900 4197590, 221170 4197590, 236722 4204770))'),
        false, 200, true
    )

SQL Example

SELECT RS_Clip(
        RS_FromGeoTiff(content), 1,
        ST_GeomFromWKT('POLYGON ((236722 4204770, 243900 4204770, 243900 4197590, 221170 4197590, 236722 4204770))'),
        false, 200, false
    )