散景时间图

Question

I am experimenting with time plots such as this example from bokeh . Is it possible to create minor ticks for the x-axis? I tried all the different options inside p.xaxis.minor but none seemed useful.

Here's the code from example:

import pandas as pd
from bokeh.plotting import figure, output_file, show

AAPL = pd.read_csv(
        "http://ichart.yahoo.com/table.csv?s=AAPL&a=0&b=1&c=2000&d=0&e=1&f=2010",
        parse_dates=['Date']
    )

output_file("datetime.html")

# create a new plot with a datetime axis type
p = figure(width=800, height=250, x_axis_type="datetime")

p.line(AAPL['Date'], AAPL['Close'], color='navy', alpha=0.5)

show(p)

And the image:

From what it seems it's automatically turned off, and the x-axis updates properly as you zoom in, but it would be great to include minor ticks for visualization purpose.

Answer 1

As of Bokeh 0.10, the BokehJS DatetimeTicker sets num_minor_ticks to zero on the internal tickers that it uses:

https://github.com/bokeh/bokeh/blob/master/bokehjs/src/coffee/ticking/datetime_ticker.coffee#L23

There is currently no simple way exposed to override this (You could write some JavaScript to reach in directly, but that would be a pain). I am not sure if this state of affairs is due to some inherent problem with minor ticks and datatime ranges, or if this was merely an oversight. Please make a new issue on the Bokeh GH issue tracker so it can be investigated:

https://github.com/bokeh/bokeh/issues