library packages

.venv/lib/python3.12/site-packages/geopandas/tools/_random.py

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+from warnings import warn
+
+import numpy
+
+from shapely.geometry import MultiPoint
+
+from geopandas.array import from_shapely, points_from_xy
+from geopandas.geoseries import GeoSeries
+
+
+def uniform(geom, size, rng=None):
+    """
+
+    Sample uniformly at random from a geometry.
+
+    For polygons, this samples uniformly within the area of the polygon. For lines,
+    this samples uniformly along the length of the linestring. For multi-part
+    geometries, the weights of each part are selected according to their relevant
+    attribute (area for Polygons, length for LineStrings), and then points are
+    sampled from each part uniformly.
+
+    Any other geometry type (e.g. Point, GeometryCollection) are ignored, and an
+    empty MultiPoint geometry is returned.
+
+    Parameters
+    ----------
+    geom : any shapely.geometry.BaseGeometry type
+        the shape that describes the area in which to sample.
+
+    size : integer
+        an integer denoting how many points to sample
+
+    Returns
+    -------
+    shapely.MultiPoint geometry containing the sampled points
+
+    Examples
+    --------
+    >>> from shapely.geometry import box
+    >>> square = box(0,0,1,1)
+    >>> uniform(square, size=102) # doctest: +SKIP
+    """
+    generator = numpy.random.default_rng(seed=rng)
+
+    if geom is None or geom.is_empty:
+        return MultiPoint()
+
+    if geom.geom_type in ("Polygon", "MultiPolygon"):
+        return _uniform_polygon(geom, size=size, generator=generator)
+
+    if geom.geom_type in ("LineString", "MultiLineString"):
+        return _uniform_line(geom, size=size, generator=generator)
+
+    warn(
+        f"Sampling is not supported for {geom.geom_type} geometry type.",
+        UserWarning,
+        stacklevel=8,
+    )
+    return MultiPoint()
+
+
+def _uniform_line(geom, size, generator):
+    """
+    Sample points from an input shapely linestring
+    """
+
+    fracs = generator.uniform(size=size)
+    return from_shapely(geom.interpolate(fracs, normalized=True)).union_all()
+
+
+def _uniform_polygon(geom, size, generator):
+    """
+    Sample uniformly from within a polygon using batched sampling.
+    """
+    xmin, ymin, xmax, ymax = geom.bounds
+    candidates = []
+    while len(candidates) < size:
+        batch = points_from_xy(
+            x=generator.uniform(xmin, xmax, size=size),
+            y=generator.uniform(ymin, ymax, size=size),
+        )
+        valid_samples = batch[batch.sindex.query(geom, predicate="contains")]
+        candidates.extend(valid_samples)
+    return GeoSeries(candidates[:size]).union_all()