dtoolkit.geoaccessor.geodataframe.toposimplify#

dtoolkit.geoaccessor.geodataframe.toposimplify(df: GeoDataFrame, /, tolerance: float, simplify_algorithm: Literal['dp', 'vw'] = 'dp', simplify_with: Literal['shapely', 'simplification'] = 'shapely', prevent_oversimplify: bool = True) → GeoDataFrame[source]#

Returns a GeoDataFrame containing a simplified representation of each geometry. Similar to simplify(), but keeps shared edges.

../../_static/simplify-vs-toposimplify.png

Parameters:

tolerancefloat

All parts of a simplified geometry will be no more than tolerance distance from the original.

simplify_algorithm{‘dp’, ‘vw’}, default ‘dp’

vw will only be selected if simplify_with is set to simplification.

dp : Douglas-Peucker

vw : Visvalingam-Whyatt

simplify_with{‘shapely’, ‘simplification’}, default ‘shapely’

Sets the package to use for simplifying. Shapely adopts solely Douglas-Peucker and simplification both Douglas-Peucker and Visvalingam-Whyatt. The package simplification is known to be quicker than shapely.

prevent_oversimplifybool, default True

If True, the simplification is slower, but the likelihood of producing valid geometries is higher as it prevents oversimplification. Simplification happens on paths separately, so this setting is especially relevant for rings with no partial shared paths. This is also known as a topology-preserving variant of simplification.

Returns:

GeoDataFrame

Raises:

ModuleNotFoundError

If don’t have module named ‘topojson’.
If don’t have module named ‘simplification’.

See also

geopandas.GeoSeries.simplify
dtoolkit.geoaccessor.geoseries.toposimplify
dtoolkit.geoaccessor.geodataframe.toposimplify
topojson.Topology.toposimplify: https://mattijn.github.io/topojson/api/topojson.core.topology.html#toposimplify

Examples

>>> import dtoolkit.geoaccessor
>>> import geopandas as gpd
>>> df = (
...     gpd.read_file(gpd.datasets.get_path("naturalearth_lowres"))
...     .query('continent == "Africa"')
... )
>>> df.head()
       pop_est  ...                                           geometry
1   58005463.0  ...  POLYGON ((33.90371 -0.95000, 34.07262 -1.05982...
2     603253.0  ...  POLYGON ((-8.66559 27.65643, -8.66512 27.58948...
11  86790567.0  ...  POLYGON ((29.34000 -4.49998, 29.51999 -5.41998...
12  10192317.3  ...  POLYGON ((41.58513 -1.68325, 40.99300 -0.85829...
13  52573973.0  ...  POLYGON ((39.20222 -4.67677, 37.76690 -3.67712...

[5 rows x 6 columns]
>>> df.toposimplify(0.1).head()
       pop_est  ...                                           geometry
1   58005463.0  ...  POLYGON ((33.90358 -0.94984, 30.76987 -1.01479...
2     603253.0  ...  POLYGON ((-8.66587 27.65614, -8.81778 27.65614...
11  86790567.0  ...  POLYGON ((29.34014 -4.49988, 29.27690 -3.29392...
12  10192317.3  ...  POLYGON ((41.58493 -1.68309, 42.04203 -0.91881...
13  52573973.0  ...  POLYGON ((39.20182 -4.67669, 39.60462 -4.34688...

[5 rows x 6 columns]