RS_MinConvexHull

Introduction: Returns the min convex hull geometry of the raster excluding the NoDataBandValue band pixels, in the given band. If no band is specified, all the bands are considered when creating the min convex hull of the raster. The created geometry representing the min convex hull has world coordinates of the raster in its CRS as the corner coordinates.

Note

If the specified band does not exist in the raster, RS_MinConvexHull throws an IllegalArgumentException

Format:

RS_MinConvexHull(raster: Raster)

RS_MinConvexHull(raster: Raster, band: Integer)

Since: v1.5.0

SQL Example

val inputDf = Seq((Seq(0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0),
        Seq(0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0))).toDF("values2", "values1")
inputDf.selectExpr("ST_AsText(RS_MinConvexHull(RS_AddBandFromArray(" +
        "RS_AddBandFromArray(RS_MakeEmptyRaster(2, 5, 5, 0, 0, 1, -1, 0, 0, 0), values1, 1, 0), values2, 2, 0))) as minConvexHullAll").show()

Output:

+----------------------------------------+
|minConvexHullAll                        |
+----------------------------------------+
|POLYGON ((0 -1, 4 -1, 4 -5, 0 -5, 0 -1))|
+----------------------------------------+

SQL Example

val inputDf = Seq((Seq(0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0),
        Seq(0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0))).toDF("values2", "values1")
inputDf.selectExpr("ST_AsText(RS_MinConvexHull(RS_AddBandFromArray(" +
  "RS_AddBandFromArray(RS_MakeEmptyRaster(2, 5, 5, 0, 0, 1, -1, 0, 0, 0), values1, 1, 0), values2, 2, 0), 1)) as minConvexHull1").show()

Output:

+----------------------------------------+
|minConvexHull1                          |
+----------------------------------------+
|POLYGON ((1 -1, 4 -1, 4 -5, 1 -5, 1 -1))|
+----------------------------------------+

SQL Example

SELECT RS_MinConvexHull(raster, 3) from rasters;

Output:

Provided band index 3 does not lie in the raster