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Cmocean Colorscales in Python

How to make Cmocean Colorscales in Python with Plotly.

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cmocean

cmocean is a package containing colormaps for commonly-used oceanographic variables. Below we provide a function to convert a cmocean colormap to a Plotly colorscale. Check out all of the cmocean colormaps below!

Imports

In [2]:
import plotly.plotly as py
import plotly.graph_objs as go
from plotly import tools

import cmocean

import numpy as np
import os

Defining Colormaps

In [3]:
import cmocean

def cmocean_to_plotly(cmap, pl_entries):
    h = 1.0/(pl_entries-1)
    pl_colorscale = []
    
    for k in range(pl_entries):
        C = map(np.uint8, np.array(cmap(k*h)[:3])*255)
        pl_colorscale.append([k*h, 'rgb'+str((C[0], C[1], C[2]))])
        
    return pl_colorscale

The examples data can be downloaded from here.

In [4]:
# Plotting the colorscale.

example_dir = os.path.join(os.path.dirname('__file__'), "examples")
hist2d = np.loadtxt(os.path.join(example_dir, "hist2d.txt"))
st_helens = np.loadtxt(os.path.join(example_dir,
                                        "st-helens_before-modified.txt.gz")).T   
dx = dy = 0.05  
y, x = np.mgrid[-5 : 5 + dy : dy, -5 : 10 + dx : dx]
z = np.sin(x)**10 + np.cos(10 + y*x) + np.cos(x) + 0.2*y + 0.1*x

elem_len = [len(hist2d), len(st_helens), len(z)]
max_len = max(elem_len)
    
def colorscale_plot(colorscale, title):    
    trace1 = go.Heatmap(z=hist2d, colorscale=colorscale, showscale=False)
    trace2 = go.Heatmap(z=st_helens, colorscale=colorscale, y0=-5, x0=-5)
    trace3 = go.Heatmap(z=z,colorscale=colorscale, showscale=False)
    
    fig = tools.make_subplots(rows=1, cols=3, print_grid=False)
    fig.append_trace(trace1, 1, 1)
    fig.append_trace(trace2, 1, 2)
    fig.append_trace(trace3, 1, 3)
    
    fig['layout'].update(title=title)
    fig['layout']['xaxis2'].update(range=[0, 450])
    fig['layout']['yaxis2'].update(range=[0, 270])
    
    return fig

Thermal

In [5]:
thermal = cmocean_to_plotly(cmocean.cm.thermal, max_len)
py.iplot(colorscale_plot(colorscale=thermal, title='Thermal'))
Out[5]:

Haline

In [8]:
haline = cmocean_to_plotly(cmocean.cm.haline, max_len)
py.iplot(colorscale_plot(colorscale=haline, title='Haline'))
Out[8]:

Solar

In [9]:
solar = cmocean_to_plotly(cmocean.cm.solar, max_len)
py.iplot(colorscale_plot(colorscale=solar, title='Solar'))
Out[9]:

Ice

In [10]:
ice = cmocean_to_plotly(cmocean.cm.ice, max_len)
py.iplot(colorscale_plot(colorscale=ice, title='Ice'))
Out[10]:

Gray

In [11]:
gray = cmocean_to_plotly(cmocean.cm.gray, max_len)
py.iplot(colorscale_plot(colorscale=gray, title='Gray'))
Out[11]:

Oxy

In [12]:
oxy = cmocean_to_plotly(cmocean.cm.oxy, max_len)
py.iplot(colorscale_plot(colorscale=oxy, title='Oxy'))
Out[12]:

Deep

In [13]:
deep = cmocean_to_plotly(cmocean.cm.deep, max_len)
py.iplot(colorscale_plot(colorscale=deep, title='Deep'))
Out[13]:

Dense

In [15]:
dense = cmocean_to_plotly(cmocean.cm.dense, max_len)
py.iplot(colorscale_plot(colorscale=dense, title='Dense'))
Out[15]:

Algae

In [16]:
algae = cmocean_to_plotly(cmocean.cm.algae, max_len)
py.iplot(colorscale_plot(colorscale=algae, title='Algae'))
Out[16]:

Matter

In [17]:
matter = cmocean_to_plotly(cmocean.cm.matter, max_len)
py.iplot(colorscale_plot(colorscale=matter, title='Matter'))
Out[17]:

Turbid

In [18]:
turbid = cmocean_to_plotly(cmocean.cm.turbid, max_len)
py.iplot(colorscale_plot(colorscale=turbid, title='Turbid'))
Out[18]:

Speed

In [20]:
speed = cmocean_to_plotly(cmocean.cm.speed, max_len)
py.iplot(colorscale_plot(colorscale=speed, title='Speed'))
Out[20]:

Amp

In [21]:
amp = cmocean_to_plotly(cmocean.cm.amp, max_len)
py.iplot(colorscale_plot(colorscale=amp, title='Amp'))
Out[21]:

Tempo

In [22]:
tempo = cmocean_to_plotly(cmocean.cm.tempo, max_len)
py.iplot(colorscale_plot(colorscale=tempo, title='Tempo'))
Out[22]:

Phase

In [23]:
phase = cmocean_to_plotly(cmocean.cm.phase, max_len)
py.iplot(colorscale_plot(colorscale=phase, title='Phase'))
Out[23]:

Balance

In [24]:
balance = cmocean_to_plotly(cmocean.cm.balance, max_len)
py.iplot(colorscale_plot(colorscale=balance, title='Balance'))
Out[24]:

Delta

In [25]:
delta = cmocean_to_plotly(cmocean.cm.delta, max_len)
py.iplot(colorscale_plot(colorscale=delta, title='Delta'))
Out[25]:

Curl

In [26]:
curl = cmocean_to_plotly(cmocean.cm.curl, max_len)
py.iplot(colorscale_plot(colorscale=curl, title='Curl'))
Out[26]:

Reference

Learn more about Plotly colorscales here: https://plot.ly/python/colorscales/

Acknowledgment

Special thanks to Kristen Thyng for the statistics of colormaps.

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