pointpats.f_test¶
- pointpats.f_test(coordinates, support=None, distances=None, metric='euclidean', hull=None, edge_correction=None, keep_simulations=False, n_simulations=9999)[source]¶
Ripley’s F function
The so-called “empty space” function, this is the cumulative density function of the distances from a random set of points to the known points in the pattern.
When the estimated statistic is larger than simulated values at a given distance, then the pattern is considered “dispersed” or “regular”
- Parameters:
- coordinatesnumpy.ndarray, (n,2)
input coordinates to function
- supporttuple of length 1, 2, or 3, int, or numpy.ndarray
tuple, encoding (stop,), (start, stop), or (start, stop, num) int, encoding number of equally-spaced intervals numpy.ndarray, used directly within numpy.histogram
- distances: numpy.ndarray, (n, p) or (p,)
distances from every point in a random point set of size p to some point in coordinates
- metric: str or callable
distance metric to use when building search tree
- hull: bounding box, scipy.spatial.ConvexHull, shapely.geometry.Polygon
the hull used to construct a random sample pattern, if distances is None
- edge_correction: bool or str
whether or not to conduct edge correction. Not yet implemented.
- keep_simulations: bool
whether or not to keep the simulation envelopes. If so, will be returned as the result’s simulations attribute
- n_simulations: int
how many simulations to conduct, assuming that the reference pattern has complete spatial randomness.
- Returns:
- a named tuple with properties
- support, the exact distance values used to evalute the statistic
- statistic, the values of the statistic at each distance
- pvalue, the percent of simulations that were as extreme as the observed value
- simulations, the distribution of simulated statistics (shaped (n_simulations, n_support_points))
or None if keep_simulations=False (which is the default)