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# GeoSeries.constrained_delaunay_triangles

> Return the constrained Delaunay triangulation of each polygon.

Return the constrained Delaunay triangulation of each polygon.

The edges of each input polygon are included in the resulting triangle
edges. The result for each row is a `GeometryCollection` of polygons.

## Signature

```python theme={"system"}
constrained_delaunay_triangles() -> GeoSeries
```

## Returns

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

**See also**

* `GeoSeries.delaunay_triangles`: unconstrained Delaunay triangulation

## Examples

```python theme={"system"}
>>> from sedona.spark.geopandas import GeoSeries
>>> from shapely.geometry import Polygon
>>> s = GeoSeries([Polygon([(0, 0), (1, 1), (0, 1)])])
>>> s.constrained_delaunay_triangles()
0    GEOMETRYCOLLECTION (POLYGON ((0 0, 0 1, 1 1, 0...
dtype: geometry
```


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