QGIS/resources/function_help/json/single_sided_buffer

{
  "name": "single_sided_buffer",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Returns a geometry formed by buffering out just one side of a linestring geometry. Distances are in the Spatial Reference System of this geometry.",
  "arguments": [{
    "arg": "geometry",
    "description": "a (multi)linestring geometry"
  }, {
    "arg": "distance",
    "description": "buffer distance. Positive values will be buffered to the left of lines, negative values to the right"
  }, {
    "arg": "segments",
    "optional": true,
    "default": "8",
    "description": "number of segments to use to represent a quarter circle when a round join style is used. A larger number results in a smoother buffer with more nodes."
  }, {
    "arg": "join",
    "optional": true,
    "default": "1",
    "description": "join style for corners, where 1 = round, 2 = miter and 3 = bevel"
  }, {
    "arg": "miter_limit",
    "optional": true,
    "default": "2.0",
    "description": "limit on the miter ratio used for very sharp corners (when using miter joins only)"
  }],
  "examples": [{
    "expression": "single_sided_buffer(@geometry, 10.5)",
    "returns": "line buffered to the left by 10.5 units"
  }, {
    "expression": "single_sided_buffer(@geometry, -10.5)",
    "returns": "line buffered to the right by 10.5 units"
  }, {
    "expression": "single_sided_buffer(@geometry, 10.5, segments:=16, join:=1)",
    "returns": "line buffered to the left by 10.5 units, using more segments to result in a smoother buffer"
  }, {
    "expression": "single_sided_buffer(@geometry, 10.5, join:=3)",
    "returns": "line buffered to the left by 10.5 units, using a beveled join"
  }],
  "tags": ["buffering", "spatial", "reference", "system", "linestring", "formed", "distances", "side"]
}