> ## Documentation Index
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> Use this file to discover all available pages before exploring further.

# GeoDataFrame.union

> Return a GeoSeries of the union of points in each aligned geometry with other.

Return a `GeoSeries` of the union of points in each aligned geometry
with `other`.

The operation works on a 1-to-1 row-wise manner.

## Signature

```python theme={"system"}
union(other, align=None)
```

## Parameters

<ParamField path="other" type="Geoseries or geometric object" required>
  The Geoseries (elementwise) or geometric object to find the
  union with.
</ParamField>

<ParamField path="align" type="bool | None (default None)" default="None">
  If True, automatically aligns GeoSeries based on their indices.
  If False, the order of elements is preserved. None defaults to True.
</ParamField>

## Returns

<ResponseField name="return" type="GeoSeries" />

**See also**

* `GeoSeries.symmetric_difference`
* `GeoSeries.difference`
* `GeoSeries.intersection`

## Examples

```python theme={"system"}
>>> from sedona.spark.geopandas import GeoSeries
>>> from shapely.geometry import Polygon, LineString, Point
>>> s = GeoSeries(
...     [
...         Polygon([(0, 0), (2, 2), (0, 2)]),
...         Polygon([(0, 0), (2, 2), (0, 2)]),
...         LineString([(0, 0), (2, 2)]),
...         LineString([(2, 0), (0, 2)]),
...         Point(0, 1),
...     ],
... )
>>> s2 = GeoSeries(
...     [
...         Polygon([(0, 0), (1, 1), (0, 1)]),
...         LineString([(1, 0), (1, 3)]),
...         LineString([(2, 0), (0, 2)]),
...         Point(1, 1),
...         Point(0, 1),
...     ],
...     index=range(1, 6),
... )
```

```python theme={"system"}
>>> s
0    POLYGON ((0 0, 2 2, 0 2, 0 0))
1    POLYGON ((0 0, 2 2, 0 2, 0 0))
2             LINESTRING (0 0, 2 2)
3             LINESTRING (2 0, 0 2)
4                       POINT (0 1)
dtype: geometry
```

```python theme={"system"}
>>> s2
1    POLYGON ((0 0, 1 1, 0 1, 0 0))
2             LINESTRING (1 0, 1 3)
3             LINESTRING (2 0, 0 2)
4                       POINT (1 1)
5                       POINT (0 1)
dtype: geometry
```

We can do union of each geometry and a single shapely geometry:

```python theme={"system"}
>>> s.union(Polygon([(0, 0), (1, 1), (0, 1)]))
0             POLYGON ((0 0, 0 1, 0 2, 2 2, 1 1, 0 0))
1             POLYGON ((0 0, 0 1, 0 2, 2 2, 1 1, 0 0))
2    GEOMETRYCOLLECTION (POLYGON ((0 0, 0 1, 1 1, 0...
3    GEOMETRYCOLLECTION (POLYGON ((0 0, 0 1, 1 1, 0...
4                       POLYGON ((0 1, 1 1, 0 0, 0 1))
dtype: geometry
```

We can also check two GeoSeries against each other, row by row.
The GeoSeries above have different indices. We can either align both GeoSeries
based on index values and compare elements with the same index using
`align=True` or ignore index and compare elements based on their matching
order using `align=False`:

```python theme={"system"}
>>> s.union(s2, align=True)
0             POLYGON ((0 0, 0 1, 0 2, 2 2, 1 1, 0 0))
1             POLYGON ((0 0, 0 1, 0 2, 2 2, 1 1, 0 0))
2    MULTILINESTRING ((0 0, 1 1), (1 1, 2 2), (1 0,...
3                                LINESTRING (2 0, 0 2)
4                            MULTIPOINT ((0 1), (1 1))
dtype: geometry
```

```python theme={"system"}
>>> s.union(s2, align=False)
0             POLYGON ((0 0, 0 1, 0 2, 2 2, 1 1, 0 0))
1    GEOMETRYCOLLECTION (POLYGON ((0 0, 0 2, 1 2, 2...
2    MULTILINESTRING ((0 0, 1 1), (1 1, 2 2), (2 0,...
3                                LINESTRING (2 0, 0 2)
4                                          POINT (0 1)
dtype: geometry
```


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