CODEWITHSUNDEEP
pythonlegendheatmapbokeh
Micawber
Micawber

Reputation: 707

bokeh - Make a legend on p.circle() according to circle size

I've made a heatmap based on the following dataframe :

   Species categories value1 value2
0      sp1       cat1  218.0    2.0
1      sp1       cat2  521.0    2.0
2      sp1       cat3  533.0    2.0
3      sp1       cat4  793.0    3.0
4      sp2       cat1  225.0    2.0
5      sp2       cat2  521.0    2.0
6      sp2       cat3  540.0    2.0
7      sp2       cat4  800.0    3.0
8      sp3       cat1  217.0    1.0
9      sp3       cat2  477.0    1.0
10     sp3       cat3  512.0    3.0
11     sp3       cat4  725.0    3.0

The column categories is the x-axis column Species is the y-axis. The heatmap elements are circles, with a color range based on the value of value1 and a circle size based on value2.

My point is about legends ; I managed to draw a color_bar scale for value1 thanks to bokeh tutorials, but I can't find how to make a legend for value2...

My code looks like something like this :

# stuff
colors = ["#75968f", "#a5bab7", "#c9d9d3", "#e2e2e2", "#dfccce", "#ddb7b1", "#cc7878", "#933b41", "#550b1d"]
mapper = LinearColorMapper(palette=colors, low=df.value1.min(), high=df.value1.max()) 

xrange = list(df.columns)
yrange = list(df.index)    

# figure    
p = figure(title='title',
       x_range=xrange, y_range=yrange,
       x_axis_location="above", plot_width=400, plot_height=200,
       toolbar_location=None, tools=""
       )

# draw the circles
p.circle(x="categories", y="Species", size="value2",
    source=df,
    fill_color={'field': "value1", 'transform': mapper},
    line_color=None)

# Legend for circles colors
color_bar = ColorBar(color_mapper=mapper, major_label_text_font_size="10pt",
                             ticker=BasicTicker(desired_num_ticks=len(colors)),
                             formatter=PrintfTickFormatter(format="%.3f"),
                             label_standoff=15, border_line_color=None, location=(0, 0))
p.add_layout(color_bar, 'right')

# missing : legend for circles size !

Is there a way to do that kind of legend ?

Upvotes: 0

Views: 826

Answers (1)

bigreddot
bigreddot

Reputation: 34618

As of Bokeh 1.4.0 this is still and open issue and there is not a good built in way to do this. I have re-triaged that issue to be in a shorter term milestone, though always with OSS, the only thing that is guaranteed to help tasks and features happen more quickly is for more contributors to pitch in.

It's possible you could create a custom extension to draw a specialized legend:

https://docs.bokeh.org/en/latest/docs/user_guide/extensions.html

That would require more iteration and back-and-forth discussion than is appropriate for an SO answer, but please feel free to come by the project Discourse.

Upvotes: 0

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