LFRic Orography (Projected)

This example demonstrates how to render a projected warped unstructured cubed-sphere mesh.

📋 Summary

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

It uses an unstructured Met Office LFRic C48 cubed-sphere of surface altitude data.

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

The mesh is transformed onto an Equidistant Cylindrical (Plate Carrée) projection.

Note that the scalar elevation values are located on the mesh nodes/points which results in the rendered colours being interpolated across the cell faces. A pyvista “warp” operation extrudes the mesh, using the same node altitude values, to highlight the global surface topography.

The warp uses compute_normals() and warp_by_scalar(). See Computing Surface Normals for further details.

Tags: Projection Transform Mesh Unstructured Warp

---

Static Scene

Interactive Scene

from __future__ import annotations

import geovista as gv
from geovista.pantry.data import lfric_orog
import geovista.theme
from geovista.transform import transform_mesh


def main() -> None:
    """Plot a projected warped LFRic unstructured mesh.

    Notes
    -----
    .. versionadded:: 0.1.0

    """
    # Load the sample data.
    sample = lfric_orog()

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

    # Transform the mesh to the Plate Carrée projection.
    mesh = transform_mesh(mesh, crs := "esri:54001")

    # Warp the mesh nodes by the surface altitude.
    mesh.compute_normals(cell_normals=False, point_normals=True, inplace=True)
    mesh.warp_by_scalar(scalars=sample.name, inplace=True, factor=200)

    # Plot the unstructured mesh.
    plotter = gv.GeoPlotter(crs=crs)
    sargs = {"title": f"{sample.name} / {sample.units}", "shadow": True}
    plotter.add_mesh(mesh, scalar_bar_args=sargs)
    plotter.add_axes()
    plotter.add_text(
        f"LFRic C48 Unstructured Cube-Sphere ({crs})",
        position="upper_left",
        font_size=10,
        shadow=True,
    )
    plotter.view_xy()
    plotter.camera.zoom(1.5)
    plotter.show()


if __name__ == "__main__":
    main()