Hex tiles

Hex tile glyphs

Bokeh can plot hexagonal tiles, which you can use to show binned aggregations and more. The hex_tile() method takes a size parameter to define the size of the hex grid and axial coordinates to specify the tiles.

import numpy as np

from bokeh.io import output_file, show
from bokeh.plotting import figure
from bokeh.util.hex import axial_to_cartesian

output_file("hex_coords.html")

q = np.array([0,  0, 0, -1, -1,  1, 1])
r = np.array([0, -1, 1,  0,  1, -1, 0])

p = figure(width=400, height=400, toolbar_location=None)
p.grid.visible = False

p.hex_tile(q, r, size=1, fill_color=["firebrick"]*3 + ["navy"]*4,
           line_color="white", alpha=0.5)

x, y = axial_to_cartesian(q, r, 1, "pointytop")

p.text(x, y, text=["(%d, %d)" % (q,r) for (q, r) in zip(q, r)],
       text_baseline="middle", text_align="center")

show(p)

Hex binning

A more practical example below computes counts per bin using the hexbin() function and plots the color mapped counts.

import numpy as np

from bokeh.io import output_file, show
from bokeh.plotting import figure
from bokeh.transform import linear_cmap
from bokeh.util.hex import hexbin

n = 50000
x = np.random.standard_normal(n)
y = np.random.standard_normal(n)

bins = hexbin(x, y, 0.1)

p = figure(tools="wheel_zoom,reset", match_aspect=True, background_fill_color='#440154')
p.grid.visible = False

p.hex_tile(q="q", r="r", size=0.1, line_color=None, source=bins,
           fill_color=linear_cmap('counts', 'Viridis256', 0, max(bins.counts)))

output_file("hex_tile.html")

show(p)

You can simplify this code by calling the hexbin() method of figure().