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Annotated Heatmaps in Python

How to make Annotated Heatmaps in Python with Plotly.


New to Plotly?

Plotly is a free and open-source graphing library for Python. We recommend you read our Getting Started guide for the latest installation or upgrade instructions, then move on to our Plotly Fundamentals tutorials or dive straight in to some Basic Charts tutorials.

Simple Annotated Heatmap

This page details the use of a figure factory. For more examples with Heatmaps, see this page.

In [1]:
import plotly.figure_factory as ff

z = [[.1, .3, .5, .7, .9],
     [1, .8, .6, .4, .2],
     [.2, 0, .5, .7, .9],
     [.9, .8, .4, .2, 0],
     [.3, .4, .5, .7, 1]]

fig = ff.create_annotated_heatmap(z)
fig.show()

Defined Colorscale

In [2]:
import plotly.figure_factory as ff

z = [[.1, .3, .5, .7],
     [1, .8, .6, .4],
     [.6, .4, .2, .0],
     [.9, .7, .5, .3]]

fig = ff.create_annotated_heatmap(z, colorscale='Viridis')
fig.show()

Custom Colorscale

In [3]:
import plotly.figure_factory as ff

z = [[.1, .3, .5, .7],
     [1.0, .8, .6, .4],
     [.6, .4, .2, 0.0],
     [.9, .7, .5, .3]]

colorscale = [[0, 'navy'], [1, 'plum']]
font_colors = ['white', 'black']
fig = ff.create_annotated_heatmap(z, colorscale=colorscale, font_colors=font_colors)
fig.show()

Custom Text and X & Y Labels

set annotation_text to a matrix with the same dimmensions as z

In [4]:
import plotly.figure_factory as ff

z = [[.1, .3, .5],
     [1.0, .8, .6],
     [.6, .4, .2]]

x = ['Team A', 'Team B', 'Team C']
y = ['Game Three', 'Game Two', 'Game One']

z_text = [['Win', 'Lose', 'Win'],
          ['Lose', 'Lose', 'Win'],
          ['Win', 'Win', 'Lose']]

fig = ff.create_annotated_heatmap(z, x=x, y=y, annotation_text=z_text, colorscale='Viridis')
fig.show()

Annotated Heatmap with numpy

In [5]:
import plotly.figure_factory as ff
import numpy as np
np.random.seed(1)

z = np.random.randn(20, 20)
z_text = np.around(z, decimals=2) # Only show rounded value (full value on hover)

fig = ff.create_annotated_heatmap(z, annotation_text=z_text, colorscale='Greys',
                                  hoverinfo='z')

# Make text size smaller
for i in range(len(fig.layout.annotations)):
    fig.layout.annotations[i].font.size = 8

fig.show()

Custom Hovertext

In [6]:
# Add Periodic Table Data
symbol = [['H', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', 'He'],
         ['Li', 'Be', '', '', '', '', '', '', '', '', '', '', 'B', 'C', 'N', 'O', 'F', 'Ne'],
         ['Na', 'Mg', '', '', '', '', '', '', '', '', '', '', 'Al', 'Si', 'P', 'S', 'Cl', 'Ar'],
         ['K', 'Ca', 'Sc', 'Ti', 'V', 'Cr', 'Mn', 'Fe', 'Co', 'Ni', 'Cu', 'Zn', 'Ga', 'Ge', 'As', 'Se', 'Br', 'Kr'],
         ['Rb ', 'Sr', 'Y', 'Zr', 'Nb', 'Mo', 'Tc', 'Ru', 'Rh', 'Pd', 'Ag', 'Cd', 'In', 'Sn', 'Sb', 'Te', 'I', 'Xe' ],
         ['Cs', 'Ba', '', 'Hf', 'Ta', 'W', 'Re', 'Os', 'Ir', 'Pt', 'Au', 'Hg', 'Tl', 'Pb', 'Bi', 'Po', 'At', 'Rn' ],
         ['Fr', 'Ra', '', 'Rf', 'Db', 'Sg', 'Bh', 'Hs', 'Mt', 'Ds', 'Rg', 'Cn', 'Uut', 'Fl', 'Uup', 'Lv', 'Uus', 'Uuo'],
         ['', '', 'La', 'Ce', 'Pr', 'Nd', 'Pm', 'Sm', 'Eu', 'Gd', 'Tb', 'Dy', 'Ho', 'Er', 'Tm', 'Yb', 'Lu', ''],
         ['', '', 'Ac', 'Th', 'Pa', 'U', 'Np', 'Pu', 'Am', 'Cm', 'Bk', 'Cf', 'Es', 'Fm', 'Md', 'No', 'Lr', '' ],
         ['', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', ''],
         ['', 'Alkali Metal', '', '', 'Transition Metal', '', '', 'Actinide', '', '', 'Semimetal', '', '', 'Halogen', '', '', '', ''],
         ['', 'Alkaline Metal', '', '', 'Lanthanide', '', '', 'Basic Metal', '', '', 'Nonmetal', '', '', 'Noble Gas', '', '', '', '']]

element = [['Hydrogen', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', 'Helium'],
           ['Lithium', 'Beryllium', '', '', '', '', '', '', '', '', '', '', 'Boron', 'Carbon', 'Nitrogen', 'Oxygen', 'Fluorine', 'Neon'],
           ['Sodium', 'Magnesium', '', '', '', '', '', '', '', '', '', '', 'Aluminium', 'Silicon', 'Phosphorus', 'Sulfur', 'Chlorine', ' Argon'],
           ['Potassium', ' Calcium', ' Scandium', ' Titanium', ' Vanadium', ' Chromium',  'Manganese', 'Iron', 'Cobalt', 'Nickel', 'Copper', 'Zinc', 'Gallium', 'Germanium', 'Arsenic', 'Selenium', 'Bromine', 'Krypton'],
           ['Rubidium', 'Strontium', 'Yttrium', 'Zirconium', 'Niobium', 'Molybdenum', 'Technetium', 'Ruthenium', 'Rhodium', 'Palladium', 'Silver', 'Cadmium', 'Indium', 'Tin', 'Antimony', 'Tellurium', 'Iodine', 'Xenon'],
           [' Cesium', ' Barium', '',  'Hafnium', 'Tantalum', 'Tungsten', 'Rhenium', 'Osmium', 'Iridium', 'Platinum', 'Gold', 'Mercury', 'Thallium', 'Lead', 'Bismuth', 'Polonium', 'Astatine', 'Radon'],
           [' Francium', ' Radium', '', 'Rutherfordium','Dubnium','Seaborgium','Bohrium','Hassium','Meitnerium','Darmstadtium','Roentgenium','Copernicium','Ununtrium','Ununquadium','Ununpentium','Ununhexium','Ununseptium','Ununoctium'],
           ['', '',  'Lanthanum', 'Cerium', 'Praseodymium', 'Neodymium', 'Promethium', 'Samarium', 'Europium', 'Gadolinium', 'Terbium', 'Dysprosium', 'Holmium', 'Erbium', 'Thulium', 'Ytterbium', 'Lutetium', ''],
           ['', '', 'Actinium', 'Thorium', 'Protactinium', 'Uranium', 'Neptunium', 'Plutonium', 'Americium', 'Curium', 'Berkelium', 'Californium', 'Einsteinium','Fermium' ,'Mendelevium', 'Nobelium', 'Lawrencium', '' ],
           ['', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', ''],
           ['', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', ''],
           ['', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '', '']]

atomic_mass = [[ 1.00794, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0,  4.002602],
     [ 6.941, 9.012182, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0,  10.811, 12.0107, 14.0067, 15.9994, 18.9984032, 20.1797],
     [ 22.98976928, 24.3050, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0,  26.9815386, 28.0855, 30.973762, 32.065, 35.453, 39.948],
     [ 39.0983, 40.078, 44.955912, 47.867, 50.9415, 51.9961, 54.938045, 55.845, 58.933195, 58.6934, 63.546, 65.38, 69.723, 72.64, 74.92160, 78.96, 79.904, 83.798],
     [ 85.4678, 87.62, 88.90585, 91.224, 92.90638, 95.96, 98, 101.07, 102.90550, 106.42, 107.8682, 112.411, 114.818, 118.710, 121.760, 127.60, 126.90447, 131.293],
     [ 132.9054519, 137.327, .0, 178.49, 180.94788, 183.84, 186.207, 190.23, 192.217, 195.084, 196.966569, 200.59, 204.3833, 207.2, 208.98040, 209, 210, 222],
     [223, 226, .0, 267, 268, 271, 272, 270, 276, 281, 280, 285, 284, 289, 288, 293, 'unknown', 294],
     [.0, .0, 138.90547, 140.116, 140.90765, 144.242, 145, 150.36, 151.964, 157.25, 158.92535, 162.500, 164.93032, 167.259, 168.93421, 173.054, 174.9668, .0],
     [.0, .0, 227, 232.03806, 231.03588, 238.02891, 237, 244, 243, 247, 247, 251, 252, 257, 258, 259, 262, .0],
     [.0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0],
     [.0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0],
     [.0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0]]

z = [[.8, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, 1.],
     [.1, .2, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .7, .8, .8, .8, .9, 1.],
     [.1, .2, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .6, .7, .8, .8, .9, 1],
     [.1, .2, .3, .3, .3, .3, .3, .3, .3, .3, .3, .3, .6, .7, .8, .8, .9, 1.],
     [.1, .2, .3, .3, .3, .3, .3, .3, .3, .3, .3, .3, .6, .6, .7, .7, .9, 1.],
     [.1, .2, .4, .3, .3, .3, .3, .3, .3, .3, .3, .3, .6, .6, .6, .7, .9, 1.],
     [.1, .2, .5, .3, .3, .3, .3, .3, .3, .3, .3, .3, .6, .6, .6, .6, .9, 1.],
     [.0, .0, .4, .4, .4, .4, .4, .4, .4, .4, .4, .4, .4, .4, .4, .4, .4, .0],
     [.0, .0, .5, .5, .5, .5, .5, .5, .5, .5, .5, .5, .5, .5, .5, .5, .5, .0],
     [.0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0, .0],
     [.1, .1, .1, .3, .3, .3, .5, .5, .5, .7, .7, .7, .9, .9, .9, .0, .0, .0],
     [.2, .2, .2, .4, .4, .4, .6, .6, .6, .8, .8, .8, 1., 1., 1., .0, .0, .0]]

# Display element name and atomic mass on hover
hover=[]
for x in range(len(symbol)):
    hover.append([i + '<br>' + 'Atomic Mass: ' + str(j)
                      for i, j in zip(element[x], atomic_mass[x])])

# Invert Matrices
symbol = symbol[::-1]
hover = hover[::-1]
z = z[::-1]

# Set Colorscale
colorscale=[[0.0, 'rgb(255,255,255)'], [.2, 'rgb(255, 255, 153)'],
            [.4, 'rgb(153, 255, 204)'], [.6, 'rgb(179, 217, 255)'],
            [.8, 'rgb(240, 179, 255)'],[1.0, 'rgb(255, 77, 148)']]

# Make Annotated Heatmap
fig = ff.create_annotated_heatmap(z, annotation_text=symbol, text=hover,
                                 colorscale=colorscale, font_colors=['black'], hoverinfo='text')
fig.update_layout(title_text='Periodic Table')
fig.show()

Reference

For more info on Plotly heatmaps, see: https://plotly.com/python/reference/#heatmap.
For more info on using colorscales with Plotly see: https://plotly.com/python/heatmap-and-contour-colorscales/
For more info on ff.create_annotated_heatmap(), see the full function reference

What About Dash?

Dash is an open-source framework for building analytical applications, with no Javascript required, and it is tightly integrated with the Plotly graphing library.

Learn about how to install Dash at https://dash.plot.ly/installation.

Everywhere in this page that you see fig.show(), you can display the same figure in a Dash application by passing it to the figure argument of the Graph component from the built-in dash_core_components package like this:

import plotly.graph_objects as go # or plotly.express as px
fig = go.Figure() # or any Plotly Express function e.g. px.bar(...)
# fig.add_trace( ... )
# fig.update_layout( ... )

import dash
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()
app.layout = html.Div([
    dcc.Graph(figure=fig)
])

app.run_server(debug=True, use_reloader=False)  # Turn off reloader if inside Jupyter