teradataml.geospatial.geodataframecolumn.GeoDataFrameColumn.union = union(self, geom_column)

DESCRIPTION:
    Returns a Geometry value that represents the point set union of two
    Geometry values.
 
PARAMETERS:
    geom_column:
        Required Argument.
        Specifies the other Geometry value.
        Types: str, ColumnExpression, GeometryType
 
SUPPORTED GEOMETRY TYPES:
    All Geometry types except geometry collections.
    Note:
        This method can be called on 3D geometries (those that include Z
        coordinates). However, the Z coordinate is ignored in method
        calculations. Consequently, any Z coordinates returned by this
        method should be ignored. Teradata recommends using the make_2D()
        method to strip out the Z coordinates of the return value.
 
RAISES:
    TypeError, ValueError, TeradataMlException
 
RETURNS:
    GeoDataFrameColumn
    Notes:
        Returns a Geometry type where the representation is one of the
        possible set of types in the following table, depending on the
        parameter types.
        +==============+=====+=====+==============+======+======+=======+=======+
        | a u b        | Ø   | Pnt | Line, GeoSeq | Poly | MPnt | MLine | MPoly |
        +==============+=====+=====+==============+======+======+=======+=======+
        | Ø            | Ø   | R01 | R02          | R03  | R04  | R05   | R06   |
        +--------------+-----+-----+--------------+------+------+-------+-------+
        | Pnt          | R01 | R20 | R15          | R22  | R04  | R17   | R19   |
        +--------------+-----+-----+--------------+------+------+-------+-------+
        | Line, GeoSeq | R02 | R15 | R16          | R21  | R15  | R16   | R18   |
        +--------------+-----+-----+--------------+------+------+-------+-------+
        | Poly         | R03 | R22 | R21          | R23  | R22  | R21   | R23   |
        +--------------+-----+-----+--------------+------+------+-------+-------+
        | MPnt         | R04 | R04 | R15          | R22  | R04  | R17   | R19   |
        +--------------+-----+-----+--------------+------+------+-------+-------+
        | MLine        | R05 | R17 | R16          | R21  | R17  | R16   | R18   |
        +--------------+-----+-----+--------------+------+------+-------+-------+
        | MPoly        | R06 | R19 | R18          | R23  | R19  | R18   | R23   |
        +--------------+-----+-----+--------------+------+------+-------+-------+
        Where:
            Pnt, R09    = ST_Point
            Line, R02   = ST_LineString
            Poly, R03   = ST_Polygon
            MPnt, R04   = ST_MultiPoint
            MLine, R05  = ST_MultiLineString
            MPoly, R06  = ST_MultiPolygon
            GeoSeq      = GeoSequence
            R15         = ST_LineString,
                          ST_GeomCollection of ST_Point and ST_LineString values
            R16         = ST_LineString, ST_MultiLineString
            R17         = ST_MultiLineString,
                          ST_GeomCollection of ST_Point and ST_LineString values
            R18         = ST_MultiPolygon,
                          ST_GeomCollection of ST_LineString and ST_Polygon values
            R19         = ST_MultiPolygon,
                          ST_GeomCollection of ST_Point and ST_Polygon values
            R20         = ST_Point, ST_MultiPoint
            R21         = ST_Polygon,
                          ST_GeomCollection of ST_LineString and ST_Polygon values
            R22         = ST_Polygon,
                          ST_GeomCollection of ST_Point ST_Polygon values
            R23         = ST_Polygon, ST_MultiPolygon
        Vantage converts GeoSequence types that are involved in the union()
        method to ST_LineString values. Therefore, union() never returns a
        GeoSequence type.
 
EXAMPLES:
    from teradataml import GeoDataFrame, load_example_data
    from teradataml import Point, LineString, Polygon, GeometryCollection
    # Load example data.
    load_example_data("geodataframe", "sample_shapes")
    # Create a GeoDataFrame.
    geodf = GeoDataFrame("sample_shapes")
    print(geodf)
 
    # Let's select only few columns from GeoDataFrame.
    pols_lines = geodf.select(["skey", "polygons", "linestrings"])[geodf.skey.isin([1001, 1002, 1003])]
 
    # Example 1: Get the point set union of geometries in columns 'polygons' and 'linestrings'.
    pols_lines.assign(res = pols_lines.linestrings.union(geom_column=pols_lines.polygons))
 
    # Example 2: Get the point set union of geometries in column 'polygons' and
    #            a GeometryType object - Polygon.
    # Create an object of Polygon GeometryType.
    po1 = Polygon([(0, 0), (0, 20), (20, 20), (20, 0), (0, 0)])
    # Pass the Polygon() GeometryType object as input to "geom_column" argument.
    pols_lines.assign(res = pols_lines.polygons.union(po1))