Highlighting multiple hex_tiles by hovering in bokeh

Question

I try to visualize my data in a hex map. For this I use python bokeh and the corresponding hex_tile function in the figure class. My data belongs to one of 8 different classes,

Answer 1

Following the discussion from previous post here comes the solution targeted for the OP code (Bokeh v1.1.0). What I did is:

1) Added a HoverTool

2) Added a JS callback to the HoverTool which:

• Resets the hex colors to the original ones (colors_array passed in the callback)
• Inspects the index of currently hovered hex (hovered_index)
• Gets the ip_class of currently hovered hex (hovered_ip_class)
• Walks through the data_source.data['ip_class'] and finds all hexagons with the same ip_class as the hovered one and sets a new color for it (pink)
• Send source.change.emit() signal to the BokehJS to update the model

The code:

from bokeh.plotting import figure, show, output_file
from bokeh.models import ColumnDataSource, CustomJS, HoverTool

colors_array = ["green", "green", "blue", "blue"]
x_row = [0, 1, 2, 3]
y_col = [1, 1, 1, 1]
ipc_array = ['A', 'B', 'A', 'B']

source = ColumnDataSource(data = dict(
    x = x_row,
    y = y_col,
    color = colors_array,
    ipc_class = ipc_array
))

p = figure(plot_width = 800, plot_height = 800, title = "Ipc to Square with colors", match_aspect = True,
           tools = "wheel_zoom,reset,pan", background_fill_color = '#440154')
p.grid.visible = False
p.hex_tile('x', 'y', source = source, fill_color = 'color')

###################################
code = ''' 
for (let i in cb_data.renderer.data_source.data['color'])
    cb_data.renderer.data_source.data['color'][i] = colors[i];

if (cb_data.index.indices != null) {
    const hovered_index = cb_data.index.indices[0];
    const hovered_ipc_class = cb_data.renderer.data_source.data['ipc_class'][hovered_index];
    for (let i = 0; i < cb_data.renderer.data_source.data['ipc_class'].length; i++) {
        if (cb_data.renderer.data_source.data['ipc_class'][i] == hovered_ipc_class)
            cb_data.renderer.data_source.data['color'][i] = 'pink';
    }
}
cb_data.renderer.data_source.change.emit();
'''

TOOLTIPS = [
    ("index", "$index"),
    ("(x,y)", "(@x, @y)"),
    ("ipc_class", "@ipc_class")
]

callback = CustomJS(args = dict(ipc_array = ipc_array, colors = colors_array), code = code)
hover = HoverTool(tooltips = TOOLTIPS, callback = callback)
p.add_tools(hover)
########################################

output_file("hexbin.html")

show(p)

Result: