{
  "name": "close_line",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Returns a closed line string of the input line string by appending the first point to the end of the line, if it is not already closed. If the geometry is not a line string or multi line string then the result will be NULL.",
  "arguments": [{
    "arg": "geometry",
    "description": "a line string geometry"
  }],
  "examples": [{
    "expression": "geom_to_wkt(close_line(geom_from_wkt('LINESTRING(0 0, 1 0, 1 1)')))",
    "returns": "'LineString (0 0, 1 0, 1 1, 0 0)'"
  }, {
    "expression": "geom_to_wkt(close_line(geom_from_wkt('LINESTRING(0 0, 1 0, 1 1, 0 0)')))",
    "returns": "'LineString (0 0, 1 0, 1 1, 0 0)'"
  }],
  "tags": ["first", "point", "closed", "end", "input", "appending", "result", "line", "multi"]
}