Label Points

Use string arrays in a point set to label points

from __future__ import annotations

import numpy as np

import pyvista as pv


from pyvista import examples

Label String Array

This example will label the nodes of a mesh with a given array of string labels for each of the nodes.

# Make some random points. Seed the rng for reproducibility.
rng = np.random.default_rng(seed=0)
poly = pv.PolyData(rng.random((10, 3)))

Add string labels to the point data - this associates a label with every node:

poly['My Labels'] = [f'Label {i}' for i in range(poly.n_points)]
poly

Header	Data Arrays
PolyData Information N Cells 10 N Points 10 N Strips 0 X Bounds 1.653e-02, 9.808e-01 Y Bounds 3.359e-02, 8.632e-01 Z Bounds 2.739e-03, 9.972e-01 N Arrays 1	Name Field Type N Comp Min Max My Labels Points 1 nan nan

Now plot the points with labels using add_point_labels().

pl = pv.Plotter()
pl.add_point_labels(poly, 'My Labels', point_size=20, font_size=36)
pl.show()

Label Node Locations

This example will label the nodes of a mesh with their coordinate locations

# Load example beam file
grid = pv.UnstructuredGrid(examples.hexbeamfile)

Create plotting class and add the unstructured grid

pl = pv.Plotter()
pl.add_mesh(grid, show_edges=True, color='lightblue')

# Add labels to points on the yz plane (where x == 0)
points = grid.points
mask = points[:, 0] == 0
pl.add_point_labels(points[mask], points[mask].tolist(), point_size=20, font_size=36)

pl.camera_position = pv.CameraPosition(
    position=(-1.5, 1.5, 3.0), focal_point=(0.05, 0.6, 1.2), viewup=(0.2, 0.9, -0.25)
)

pl.show()

Label Scalar Values

This example will label each point with their scalar values

mesh = examples.load_uniform().slice()

pl = pv.Plotter()

# Add the mesh:
pl.add_mesh(mesh, scalars='Spatial Point Data', show_edges=True)
# Add the points with scalar labels:
pl.add_point_scalar_labels(mesh, 'Spatial Point Data', point_size=20, font_size=36)

# Use a nice camera position:
pl.camera_position = pv.CameraPosition(
    position=(7, 4, 5), focal_point=(4.4, 7.0, 7.2), viewup=(0.8, 0.5, 0.25)
)

pl.show()

Tags: plot