QGIS/resources/function_help/json/is_valid

{
  "name": "is_valid",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Returns TRUE if a geometry is valid; if it is well-formed in 2D according to the OGC rules.",
  "arguments": [{
    "arg": "geometry",
    "description": "a geometry"
  }],
  "examples": [{
    "expression": "is_valid(geom_from_wkt('LINESTRING(0 0, 1 1, 2 2, 0 0)'))",
    "returns": "TRUE"
  }, {
    "expression": "is_valid(geom_from_wkt('LINESTRING(0 0)'))",
    "returns": "FALSE"
  }],
  "tags": ["rules", "valid", "ogc", "according", "formed"]
}