Clouds

This example demonstrates how to render an unstructured cloud mesh.

📋 Summary

Creates a mesh from 1D latitude and longitude unstructured cell points.

The resulting mesh contains quad cells and is constructed from CF UGRID unstructured cell points and connectivity.

It uses an unstructured Met Office high-resolution LFRic C768 cubed-sphere of High Cloud Amount located on the mesh faces/cells.

Note that a threshold is applied to remove low-valued Cloud Amount cells, and a custom colormap is applied to the mesh to crop out unwanted darker shades.

A Natural Earth base layer is also rendered along with Natural Earth coastlines.

🏷 Tags: component: coastlines component: texture domain: meteorology filter: threshold load: unstructured resolution: high style: colormap version: 0.4.0

---

Static Scene

Interactive Scene

from __future__ import annotations

import cmocean
from cmocean.tools import crop_by_percent

import geovista as gv
from geovista.pantry.data import cloud_amount

# Multiplication factor of the zlevel for cloud surface stratification.
ZLEVEL_FACTOR: int = 75


def main() -> None:
    """Plot an unstructured cloud mesh.

    Notes
    -----
    .. versionadded:: 0.4.0

    """
    # Define the data range.
    clim = (cmin := 0.3, 1.0)

    # Customise the colormap.
    cmap = crop_by_percent(cmocean.cm.gray, 40, which="min")

    # Create the plotter.
    p = gv.GeoPlotter()

    # Load the sample data.
    sample = cloud_amount(preference="high")

    # Create the mesh from the sample data.
    mesh = gv.Transform.from_unstructured(
        sample.lons,
        sample.lats,
        connectivity=sample.connectivity,
        data=sample.data,
        start_index=sample.start_index,
    )

    # Remove cells from the mesh below the specified threshold.
    mesh = mesh.threshold(cmin)

    p.add_mesh(
        mesh,
        clim=clim,
        cmap=cmap,
        show_scalar_bar=False,
        zlevel=ZLEVEL_FACTOR,
    )

    # Force zlevel alignment of coastlines and base layer.
    p.add_base_layer(texture=gv.natural_earth_1(), zlevel=0)
    p.add_coastlines()
    p.add_text(
        "High Cloud Amount",
        position="upper_left",
        font_size=10,
    )

    # Define a specific camera position.
    p.camera.zoom(1.5)

    p.add_axes()
    p.show()


if __name__ == "__main__":
    main()