sandplover.plan.compute_shoreline_radius

sandplover.plan.compute_shoreline_radius(shore_mask, origin=(0, 0), return_radii=False, **kwargs)

Radially-averaged shoreline radius.

Algorithm uses equally spaced RadialSection to calculate the distance to the shoreline.

Note

In implementation, this metric uses the last (farthest) intersection of the RadialSection at a certain azimuth and the shoreline mask, if there are multiple intersections.

See also

This function is similar to, but distinct from compute_shoreline_distance, which computes the straight-line distance between the origin and every point along the shoreline.

Parameters:

• shore_mask (ShorelineMask) – Input shoreline mask.

• origin – Origin for RadialSection objects, specified in data dimensions (not indices) along dim1, dim2 of the data. Default (0, 0).

• return_radii (bool, optional) – Whether to return the calculated radii along each section, in addition to the mean and standard deviation.

• **kwargs – Passed to _determine_equally_spaced_azimuths.

Returns:

• mean – Mean radius over all sections.

• std – Standard deviation of radii along all sections.

• radii – Array of radius values calculated along all sections. Returned only if return_radii = True.

Examples

Compute the distance to the shoreline at seven equally spaced RadialSection:

import sandplover as spl

golf = spl.sample_data.golf()
origin = np.array([golf.meta["L0"].data, golf.meta["CTR"].data]) * golf.meta["dx"].data

azimuth_kwargs = {"num": 7}
shore_mask = spl.mask.ShorelineMask(golf["eta"][-1], elevation_threshold=0)

mean_radius, std_radius = spl.plan.compute_shoreline_radius(
    shore_mask, origin=origin, **azimuth_kwargs
)

# make a map to visualize the calculation
from sandplover.plan import _determine_equally_spaced_azimuths

azimuths = _determine_equally_spaced_azimuths(**azimuth_kwargs)

fig, ax = plt.subplots()
shore_mask.show(ax=ax, ticks=True)
for a, azimuth in enumerate(azimuths):
    a_section = spl.section.RadialSection(
        golf["eta"][-1, :, :],
        azimuth=azimuth,
        origin=origin,
    )
    a_section.show_trace(ax=ax)

ax.set_title(f"{mean_radius:.0f} $\pm$ {std_radius:.0f}")

(Source code, png, hires.png)