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WebGL Heatmaps in Python

How to make webGL based heatmaps in Python with Plotly.

New to Plotly?¶

Plotly's Python library is free and open source! Get started by downloading the client and reading the primer.
You can set up Plotly to work in online or offline mode, or in jupyter notebooks.
We also have a quick-reference cheatsheet (new!) to help you get started!

Version Check¶

Plotly's python package is updated frequently. Run pip install plotly --upgrade to use the latest version.

In [1]:
import plotly
plotly.__version__
Out[1]:
'3.1.0'

Imports¶

In [25]:
import plotly.plotly as py

import requests
from PIL import Image
from io import BytesIO

Create a HeatmapGL from an Image¶

Process the image for generating heatmap:

In [21]:
image_url = 'https://images.plot.ly/plotly-documentation/images/heatmap-galaxy.jpg'

response = requests.get(image_url)
img = Image.open(BytesIO(response.content))
img
Out[21]:
In [23]:
arr = np.array(img)
z_data = []

for i in range(500):
    k = []
    for j in range(500):
        k.append(sum(arr[i][j]))
    z_data.append(k)

Create the WebGL Heatmap

In [24]:
trace = dict(type='heatmapgl', z=z_data, colorscale='Picnic')
data = [trace]

layout = dict(width=700, height=700)
fig = dict(data=data, layout=layout)
py.iplot(fig, filename='basic heatmapgl')
Out[24]:

Reference¶

See https://plot.ly/python/reference/#heatmapgl for more information and chart attribute options!

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