QGIS/resources/function_help/json/exterior_ring

{
  "name": "exterior_ring",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Returns a line string representing the exterior ring of a polygon geometry. If the geometry is not a polygon then the result will be NULL.",
  "arguments": [{
    "arg": "geometry",
    "description": "a polygon geometry"
  }],
  "examples": [{
    "expression": "geom_to_wkt(exterior_ring(geom_from_wkt('POLYGON((-1 -1, 4 0, 4 2, 0 2, -1 -1),( 0.1 0.1, 0.1 0.2, 0.2 0.2, 0.2, 0.1, 0.1 0.1))')))",
    "returns": "'LineString (-1 -1, 4 0, 4 2, 0 2, -1 -1)'"
  }],
  "tags": ["polygon", "line", "ring", "exterior", "result", "representing"]
}