Segmenting a wrapping matplotlib plot

Segmented Plot

# See -- http://stackoverflow.com/q/27138751/656912

from __future__ import division

import ephem
import matplotlib
import matplotlib.pyplot
import numpy

def segment_plot(x, y, ax, color='b', lw=1, ls='-', lims=[0, 24], thresh=0.95):

    def unlink_wrap(dat, lims=lims, thresh=thresh):
        jump = numpy.nonzero(numpy.abs(numpy.diff(dat)) > ((lims[1] - lims[0]) * thresh))[0]
        lasti = 0
        for ind in jump:
            yield slice(lasti, ind + 1)
            lasti = ind + 1
        yield slice(lasti, len(dat))

    def pad_segments(x, y, slc):
        x_values = x[slc]
        y_values = y[slc]
        if slc.stop < len(x):
            x_values = numpy.concatenate((x_values, [x[slc.stop + 1] + 24]))
            y_values = numpy.concatenate((y_values, [y[slc.stop + 1]]))
        if slc.start > 0:
            x_values = numpy.concatenate(([x[slc.start - 1] - 24], x_values))
            y_values = numpy.concatenate(([y[slc.start - 1]], y_values))
        return x_values, y_values

    for slc in unlink_wrap(x):
        x_vals, y_vals = pad_segments(x, y, slc)
        ax.plot(x_vals, y_vals, ls=ls, color=color, lw=lw)

base_date = ephem.Date(b'2014/11/25')
date_range = numpy.array(range(-182, 2*356))

fig, ax = matplotlib.pyplot.subplots()

for (planet, style) in [(ephem.Moon, {'color': '0.9'}),
                        (ephem.Sun,  {'color': 'y', 'lw': '3'}),
                        (ephem.Mars,  {'color': 'r'}),
                        (ephem.Jupiter,  {'color': 'g'})]:
    segment_plot(numpy.array([12*ep.ra/numpy.pi for ep in [planet(base_date + d) for d in date_range]]), date_range,
                 ax, **style)

ax.set(xlim=[0, 24])
ax.set(ylim=[min(date_range), max(date_range)])

Comments:

1. According to the 'flat is better than nested' Python principal I believe it is bad style to define functions within functions. Instead, define functions 'flat' within a module, then import only the one you call (see my 'function' fork).
2. You haven't passed the lims or thresh argument to your unlink_wrap(x) call. Thus, you won't be able to use different lims from the default values you define for that function.
3. I also created a fork that implements this as a class. Here.

Excellent! Thanks for the improvements!

You're welcome! I didn't run either of my implementations to confirm they were bug-free, so comment on them if you have problems or questions.