Scatter3d plot

The scatter3d plot creates a three-dimensional scatter plot of the data.

import plopp as pp
import scipp as sc
import numpy as np

Scatter plot using a positions vector

The easiest way to generate a scatter plot is to use a coordinate of the data array that contains data of the vector3 dtype.

We first generate some fake data, meant to represent clusters of points in a three-dimensional space.

nclusters = 100
npercluster = 1000

position = np.zeros((nclusters, npercluster, 3))
values = np.zeros((nclusters, npercluster))

for n in range(nclusters):
    center = 500.0 * (np.random.random(3) - 0.5)
    r = 20.0 * np.random.normal(size=[npercluster, 3])
    position[n, :] = r + center
    values[n, :] = np.linalg.norm(r, axis=1) + n

da = sc.DataArray(
    data=sc.array(dims=['row'], values=values.flatten(), unit='K'),
    coords={
        'position': sc.vectors(
            dims=['row'], unit='m', values=position.reshape(nclusters * npercluster, 3)
        )
    },
)
da

scipp.DataArray (3.05 MB)

• Dimensions:
  • row: 100000
• Coordinates: (1)
  • position
    (row)
    vector3
    m
    [ -15.1651176 -161.33568127 -49.62169235], [ -67.51128461 -148.8059098 -33.38572269], ..., [221.69762268 252.54935491 253.19620575], [213.47460047 213.79585372 243.67792539]

    Values:
    array([[ -15.1651176 , -161.33568127,  -49.62169235],
           [ -67.51128461, -148.8059098 ,  -33.38572269],
           [   6.44428944, -101.44589825,  -33.17659947],
           ...,
           [ 215.78748279,  220.85264231,  258.65548639],
           [ 221.69762268,  252.54935491,  253.19620575],
           [ 213.47460047,  213.79585372,  243.67792539]], shape=(100000, 3))

• Data: (1)
  • (row)
    float64
    K
    19.514, 41.198, ..., 131.654, 129.664

    Values:
    array([ 19.51377836,  41.19755761,  60.60213487, ..., 130.34019432,
           131.65363829, 129.66438496], shape=(100000,))

We then simply specify the name of the coordinate that contains the vector positions using the pos argument:

pp.scatter3d(da, pos='position', color='black', size=2)

Scatter plot with colorbar

To make a scatter plot with a colorbar mapping data values to colors, use cbar=True.

pp.scatter3d(da, pos='position', cbar=True, size=2)

Scatter plot using individual coordinates

It is also possible to create scatter plots using three individual coordinate names for the x, y, z dimensions:

time = np.linspace(0, 10, 50)
x = np.cos(time)
y = np.sin(time)

da = sc.DataArray(
    data=sc.array(dims=['row'], values=time),
    coords={
        'x': sc.array(dims=['row'], unit='m', values=x),
        'y': sc.array(dims=['row'], unit='m', values=y),
        'time': sc.array(dims=['row'], unit='s', values=time),
    },
)

pp.scatter3d(da, x='x', y='y', z='time', size=0.2, cbar=True)