code: def test_project_windbarbs(self):
      xs = np.linspace(10, 50, 2)
      X, Y = np.meshgrid(xs, xs)
      U, V = 5 * X, 1 * Y
      A = np.arctan2(V, U)
      M = np.hypot(U, V)
      crs = ccrs.PlateCarree()
      windbarbs = WindBarbs((X, Y, A, M), crs=crs)
      projection = ccrs.Orthographic()
      projected = project(windbarbs, projection=projection)
      assert projected.crs == projection
  
      xs, ys, ang, ms = (
          windbarbs.dimension_values(i) for i in range(4)
      )
      us = np.sin(ang) * -ms
      vs = np.cos(ang) * -ms
      u, v = projection.transform_vectors(crs, xs, ys, us, vs)
      a, m = np.pi / 2 - np.arctan2(-v, -u).T, np.hypot(u, v).T
  
      np.testing.assert_allclose(
          projected.dimension_values("Angle"), a.flatten()
      )
      np.testing.assert_allclose(
          projected.dimension_values("Magnitude"), m.flatten()
      )
  
file_path: geoviews/geoviews/tests/test_projection.py
imports: import numpy
  import cartopy.crs
  from geoviews.element import Image, VectorField, WindBarbs
  from geoviews.element.comparison import ComparisonTestCase
  from geoviews.operation import project
label_desc: Use image node_id 4 for calling the TestProjection obj's underlying member method code with example usage: obj.test_project_windbarbs() without return types