sandplover.plan.compute_topset_slope

sandplover.plan.compute_topset_slope(elevation_data, origin=(0, 0), elevation_threshold=0, count_threshold=5, return_slopes=False, **kwargs)

Compute the slope of a fan or delta topset.

Algorithm uses equally spaced RadialSection to calculate the slope of input elevation_data that is above elevation_threshold.

Parameters:

  • elevation_data (array-like) – Input elevation data.

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

  • elevation_threshold (float, optional) – Elevation threshold for finding the topset. Commonly, this would be sea level. Default is 0.

  • count_threshold (int, optional) – How many pixels above sea level must be identified in order to fit a line. Default is 5 points.

  • return_slopes (bool, optional) – Whether to return the calculated slopes, in addition to the mean and standard deviation.

  • **kwargs – Passed to _determine_equally_spaced_azimuths.

Returns:

  • mean – Mean slope along all sections.

  • std – Standard deviation of slope along sections.

  • slopes – Array of slope values calculated along all sections. Returned only if return_slopes = True.

Examples

See also

See also some examples using compute_topset_slope in computations here: Radially-averaged topset slope.

To make a calculation with 5 equally spaced sections on the left half of the domain only:

(Source code, png, hires.png)

../_images/sandplover-plan-compute_topset_slope-1.png

To calculate the slope of a deposit, try something like:

>>> deposit_thickness = golf["eta"][-1, :, :] - golf["eta"][0, :, :]
>>> deposit_thickness.data[deposit_thickness == 0] = np.nan
>>> mean, std = compute_topset_slope(
...     deposit_thickness, elevation_threshold=-np.inf
... )