Wind Arrows Flow

This example demonstrates how to render fixed-length horizontal wind arrows.

📋 まとめ

The sample data contains a longitude and latitude point cloud, along with sample winds provided in the form of three separate eastward (U), northward (V), and upward (W) vector components.

The vector components are measured relative to each spatial sample point in the point cloud.

No connectivity is provided within the sample data, so each point is a separate location in a field of scattered points, and each point has an associated wind vector independent of the others. We use the geovista.bridge.Transform.from_points() method, passing the winds with the vectors keyword, along with the associated sample points to generate a point cloud mesh with attached vectors.

The wind arrows are generated from this point cloud mesh via the pyvista.DataSetFilters.glyph() method, which creates fixed-length arrows that are coloured relative to the magnitude of their associated wind vector.

Rendering with fixed-length arrows highlights the wind flow and direction, leaving colour alone to indicate magnitude.

Note that, we only use the horizontal winds (U and V) in this example, which is the most common use case.

参考

Wind Arrows for an example of rendering scaled horizontal wind arrows.

🏷 Tags: experimental 🧪 component: graticule component: texture component: vectors domain: meteorology filter: glyph load: vectors version: 0.6.0

---

Static Scene

Interactive Scene

from __future__ import annotations

import pyvista as pv

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


def main() -> None:
    """Plot fixed-length horizontal wind arrows (UV).

    Notes
    -----
    .. versionadded:: 0.6.0

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

    # Create the point cloud mesh with attached horizontal wind vectors
    # from the sample eastward (u) and northward (v) components.
    mesh = gv.Transform.from_points(
        sample.lons,
        sample.lats,
        vectors=(sample.u, sample.v),
    )

    # Generate a mesh containing arrow glyphs from the wind vectors that are
    # not scaled but instead have a fixed-length arrow. However, colour the
    # arrows relative to their associated vector magnitude.
    arrows = mesh.glyph(factor=0.1, scale=False, color_mode="vector")

    # Now render the plotter scene.
    p = gv.GeoPlotter()
    sargs = {"title": f"{sample.name} / {sample.units}"}
    p.add_mesh(arrows, cmap="magma", scalar_bar_args=sargs)
    p.add_base_layer(texture=gv.natural_earth_hypsometric())
    p.add_graticule()

    # Define a specific camera position and orientation.
    cpos = pv.CameraPosition(
        position=(-4.06882, -2.54626, -2.85930),
        focal_point=(-0.00378, 0.00517, -0.00317),
        viewup=(-0.52338, -0.11175, 0.84474),
    )
    p.camera.zoom(1.3)

    p.add_axes()
    p.show(cpos=cpos)


if __name__ == "__main__":
    main()