import regionmask

regionmask.__version__

"""
Explanation: Overlapping regions
Two or more on regions can share the same area - they overlap, as for example region 3 and 4 of the PRUDENCE regions This notebook illustrates how overlapping regions can be treated in regionmask.
In short
Thus, when creating your own Regions you need to tell regionmask if they are overlapping.
python
region = regionmask.Regions(..., overlap=True)
region = regionmask.from_geopandas(..., overlap=True)
If you have two overlapping regions and overlap=False regionmask will silently assign the gridpoints of the overlapping regions to the one with the higher number, e.g., region 4 for PRUDENCE (this may change in a future version).
Note that overlap is correctly defined in regionmask.defined_regions.
Example
To illustrate the problem we construct two regions in North America that partially overlap. One is horizontal, the other vertical.
Preparation
Import regionmask and check the version:
End of explanation
"""


import xarray as xr
import numpy as np

import cartopy.crs as ccrs
import matplotlib.pyplot as plt

from matplotlib import colors as mplc
from shapely.geometry import Polygon

import matplotlib.patheffects as pe

"""
Explanation: Other imports
End of explanation
"""


cmap = mplc.ListedColormap(["none", "#9ecae1"])

"""
Explanation: Define some colors:
End of explanation
"""


def plot_region_vh(mask):

    fg = mask.plot(
        subplot_kws=dict(projection=ccrs.PlateCarree()),
        col="region",
        cmap=cmap,
        add_colorbar=False,
        transform=ccrs.PlateCarree(),
        ec="0.5",
        lw=0.25,
    )

    for ax in fg.axes.flatten():
        region_vh[[0]].plot(ax=ax, add_label=False, line_kws=dict(color="#6a3d9a"))
        region_vh[[1]].plot(ax=ax, add_label=False, line_kws=dict(color="#ff7f00"))

        ax.set_extent([-105, -75, 25, 55], ccrs.PlateCarree())
        ax.plot(
            ds_US.LON, ds_US.lat, "*", color="0.5", ms=0.5, transform=ccrs.PlateCarree()
        )

"""
Explanation: Define helper function:
End of explanation
"""


coords_v = np.array([[-90.0, 50.0], [-90.0, 28.0], [-100.0, 28.0], [-100.0, 50.0]])
coords_h = np.array([[-80.0, 50.0], [-80.0, 40.0], [-100.0, 40.0], [-100.0, 50.0]])

"""
Explanation: Define the polygons:
End of explanation
"""


region_vh = regionmask.Regions([coords_v, coords_h])

"""
Explanation: Default behavior (overlap=False)
Fe first test what happens if we keep the default value of overlap=False:
End of explanation
"""


ds_US = regionmask.core.utils.create_lon_lat_dataarray_from_bounds(
    *(-160, -29, 2), *(76, 13, -2)
)

mask_vh = region_vh.mask_3D(ds_US)

"""
Explanation: Create a mask
End of explanation
"""


plot_region_vh(mask_vh)

"""
Explanation: Plot the masked regions:
End of explanation
"""


region_overlap = regionmask.Regions([coords_v, coords_h], overlap=True)

region_overlap

"""
Explanation: The small gray points show the gridpoint center and the vertical and horizontal lines are the gridpoint boundaries. The colored rectangles are the two regions. The vertical region has the number 1 and the horizontal region the number 2.
We can see that only the gridpoints in the lower part of the vertical (magenta) region were assigned to it. All gridpoints of the overlapping part are now assigned to the horizontal (orange) region. As mentioned the gridpoints are assigned to the region with the higher number By switching the order of the regions you could have the common gridpoints assigned to the vertical region.
Setting overlap=True
As mentioned regionmask assumes regions are not overlapping, so you need to pass overlap=True to the constructor:
End of explanation
"""


mask_overlap = region_overlap.mask_3D(ds_US)

"""
Explanation: Now it says overlap:  True - and we can again create a mask:
End of explanation
"""


plot_region_vh(mask_overlap)

"""
Explanation: and plot it
End of explanation
"""


prudence = regionmask.defined_regions.prudence
prudence

"""
Explanation: Now the gridpoints in the overlapping part are assigned to both regions.
PRUDENCE regions
The PRUDENCE regions are a real-world example of overlapping areas. The prudence regions already set overlap=True.
End of explanation
"""


proj = ccrs.LambertConformal(central_longitude=10)

text_kws = dict(
    bbox=dict(color="none"),
    path_effects=[pe.withStroke(linewidth=3, foreground="w")],
    color="#67000d",
)

ax = prudence.plot(
    projection=proj, text_kws=text_kws, resolution="50m", line_kws=dict(lw=0.75)
)


ax.set_extent([-10.0, 30.0, 40.0, 55.0], ccrs.PlateCarree())

"""
Explanation: Regions 3 and 4 overlap in Western France:
End of explanation
"""


lon = np.arange(-12, 33, 0.5)
lat = np.arange(72, 33, -0.5)

mask_prudence = prudence.mask_3D(lon, lat)

proj = ccrs.LambertConformal(central_longitude=10)

fg = mask_prudence.sel(region=[3, 4]).plot(
    subplot_kws=dict(projection=proj),
    col="region",
    cmap=cmap,
    add_colorbar=False,
    transform=ccrs.PlateCarree(),
)


for ax in fg.axes.flatten():
    regionmask.defined_regions.prudence.plot(
        ax=ax, add_label=False, resolution="50m", line_kws=dict(lw=0.75)
    )

"""
Explanation: Create mask of PRUDENCE regions
End of explanation
"""


