Shape error gallery

Gallery of contours with shape error

from matplotlib import pyplot as plt
from numpy import arange, cos, linspace, radians, sin

from py_eddy_tracker import data
from py_eddy_tracker.dataset.grid import RegularGridDataset
from py_eddy_tracker.eddy_feature import Contours
from py_eddy_tracker.generic import local_to_coordinates

Method to built circle from center coordinates

def build_circle(x0, y0, r):
    angle = radians(linspace(0, 360, 50))
    x_norm, y_norm = cos(angle), sin(angle)
    return local_to_coordinates(x_norm * r, y_norm * r, x0, y0)

We iterate over closed contours and sort with regards of shape error

g = RegularGridDataset(
    data.get_demo_path("dt_med_allsat_phy_l4_20160515_20190101.nc"),
    "longitude",
    "latitude",
)
c = Contours(g.x_c, g.y_c, g.grid("adt") * 100, arange(-50, 50, 0.2))
contours = dict()
for coll in c.iter():
    for current_contour in coll.get_paths():
        _, _, _, aerr = current_contour.fit_circle()
        i = int(aerr // 4) + 1
        if i not in contours:
            contours[i] = list()
        contours[i].append(current_contour)

We assume pixel position of grid is centered for /home/docs/checkouts/readthedocs.org/user_builds/py-eddy-tracker/conda/stable/lib/python3.10/site-packages/pyEddyTracker-3.6.1+0.g9d408e5.dirty-py3.10.egg/py_eddy_tracker/data/dt_med_allsat_phy_l4_20160515_20190101.nc

Shape error gallery

For each contour display, we display circle fitted, we work at different latitude circle could have distorsion

fig = plt.figure(figsize=(12, 12))
for i in range(1, 26):
    e_min, e_max = (i - 1) * 4, i * 4
    ax = plt.subplot(5, 5, i, title=f" {e_min} < err < {e_max}")
    ax.xaxis.set_ticklabels([])
    ax.yaxis.set_ticklabels([])
    ax.set_aspect("equal")
    ax.grid()
    if i in contours:
        for contour in contours[i]:
            x, y = contour.lon, contour.lat
            x0, y0, radius, _ = contour.fit_circle()
            if x.shape[0] > 30 and 30000 < radius < 70000:
                # Plot only first contour found
                m = ax.plot(x, y, "r")[0]
                ax.plot(*build_circle(x0, y0, radius), "g--")
                ax.plot(x0, y0, "k.")
                break
plt.tight_layout()