RS_PixelAsPolygons

Introduction: Returns a list of the polygon geometry, the pixel value and its raster X and Y coordinates for each pixel in the raster at the specified band.

RS_PixelAsPolygons

Format: RS_PixelAsPolygons(raster: Raster, band: Integer)

Return type: Array<Struct<geom: Geometry, val: Double, x: Integer, y: Integer>>

Since: v1.5.1

SQL Example

SELECT ST_AsText(RS_PixelAsPolygons(raster, 1)) from rasters

Output:

[[POLYGON ((123.19000244140625 -12, 127.19000244140625 -12, 127.19000244140625 -16, 123.19000244140625 -16, 123.19000244140625 -12)),0.0,1,1],
[POLYGON ((127.19000244140625 -12, 131.19000244140625 -12, 131.19000244140625 -16, 127.19000244140625 -16, 127.19000244140625 -12)),0.0,2,1],
[POLYGON ((131.19000244140625 -12, 135.19000244140625 -12, 135.19000244140625 -16, 131.19000244140625 -16, 131.19000244140625 -12)),0.0,3,1]]

Spark SQL example for extracting Point, value, raster x and y coordinates:

val pointDf = sedona.read...
val rasterDf = sedona.read.format("binaryFile").load("/some/path/*.tiff")
var df = sedona.read.format("binaryFile").load("/some/path/*.tiff")
df = df.selectExpr("RS_FromGeoTiff(content) as raster")

df.selectExpr(
  "explode(RS_PixelAsPolygons(raster, 1)) as exploded"
).selectExpr(
  "exploded.geom as geom",
  "exploded.value as value",
  "exploded.x as x",
  "exploded.y as y"
).show(3)

Output:

+--------------------+-----+---+---+
|                geom|value|  x|  y|
+--------------------+-----+---+---+
|POLYGON ((-130958...|  0.0|  1|  1|
|POLYGON ((-130957...|  0.0|  2|  1|
|POLYGON ((-130956...|  0.0|  3|  1|
+--------------------+-----+---+---+