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
    [ 269.1308613 -6.88299381 -114.09653175], [237.41664038 -26.2982995 -86.02735598], ..., [ 60.76310769 -72.68302422 -9.61229159], [ 27.98146596 -42.21381325 27.95863624]

    Values:
    array([[ 269.1308613 ,   -6.88299381, -114.09653175],
           [ 237.41664038,  -26.2982995 ,  -86.02735598],
           [ 241.40159959,  -14.06446819,  -81.51657581],
           ...,
           [  34.18580594,  -45.9429662 ,   -3.17489799],
           [  60.76310769,  -72.68302422,   -9.61229159],
           [  27.98146596,  -42.21381325,   27.95863624]], shape=(100000, 3))

• Data: (1)
  • (row)
    float64
    K
    37.565, 30.863, ..., 139.023, 124.781

    Values:
    array([ 37.56504452,  30.86317454,  30.31648549, ..., 118.70076253,
           139.02301646, 124.78085357], 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)