QGIS/resources/function_help/json/buffer_by_m

{
  "name": "buffer_by_m",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Creates a buffer along a line geometry where the buffer diameter varies according to the m-values at the line vertices.",
  "arguments": [{
    "arg": "geometry",
    "description": "input geometry. Must be a (multi)line geometry with m values."
  }, {
    "arg": "segments",
    "optional": true,
    "default": "8",
    "description": "number of segments to approximate quarter-circle curves in the buffer."
  }],
  "examples": [{
    "expression": "buffer_by_m(geometry:=geom_from_wkt('LINESTRINGM(1 2 0.5, 4 2 0.2)'),segments:=8)",
    "returns": "A variable width buffer starting with a diameter of 0.5 and ending with a diameter of 0.2 along the linestring geometry."
  }],
  "tags": ["line", "according", "values", "varies", "vertices", "buffer", "diameter"]
}