I was reading through the projections docs and decided to take a shot
at creating a radar chart class. The layout of the labels and legend
is really off, but other than that, this seems to work OK. I couldn't
figure out a good way to initialize the number of axes/variables, so
there's an ugly function wrapping around the class def.
Anyway, I hope this is useful to somebody:
#!/usr/bin/env python
from matplotlib.projections.polar import PolarAxes
from matplotlib.projections import register_projection
from pylab import *
def radar_factory(num_vars, frame='polygon'):
"""Create a radar chart with `num_vars` axes.
"""
# calculate evenly-spaced axis angles
theta = 2*pi * linspace(0, 1-1/float(num_vars), num_vars)
# rotate theta such that the first axis is at the top
theta += pi/2
def draw_poly_frame(self, x0, y0, r):
# TODO: should use transforms to convert (x, y) to (r, theta)
verts = [(r*cos(t) + x0, r*sin(t) + y0) for t in theta]
return Polygon(verts, closed=True)
def draw_circle_frame(self, x0, y0, r):
return Circle((x0, y0), r)
frame_dict = {'polygon': draw_poly_frame, 'circle': draw_circle_frame}
if frame not in frame_dict:
raise ValueError, 'unknown value for `frame`: %s' % frame
class RadarAxes(PolarAxes):
"""Class for creating a radar chart (a.k.a. a spider or star chart)
http://en.wikipedia.org/wiki/Radar_chart
"""
name = 'radar'
# use 1 line segment to connect specified points
RESOLUTION = 1
# define draw_frame method
draw_frame = frame_dict[frame]
def fill(self, *args, **kwargs):
"""Override fill so that line is closed by default"""
closed = kwargs.pop('closed', True)
return super(RadarAxes, self).fill(closed=closed, *args, **kwargs)
def plot(self, *args, **kwargs):
"""Override plot so that line is closed by default"""
lines = super(RadarAxes, self).plot(*args, **kwargs)
for line in lines:
self._close_line(line)
def _close_line(self, line):
x, y = line.get_data()
# FIXME: markers at x[0], y[0] get doubled-up
if x[0] != x[-1]:
x = concatenate((x, [x[0]]))
y = concatenate((y, [y[0]]))
line.set_data(x, y)
def set_varlabels(self, labels):
self.set_thetagrids(theta * 180/pi, labels)
def get_axes_patch(self):
x0, y0 = (0.5, 0.5)
r = 0.5
return self.draw_frame(x0, y0, r)
register_projection(RadarAxes)
return theta
if __name__ == '__main__':
N = 5
theta = radar_factory(N)
# theta = radar_factory(N, frame='circle')
ax = subplot(111, projection='radar')
labels = ['humor', 'sarcasm', 'news content', 'America', 'overall']
colbert = [8, 9, 5, 9, 7]
dailyshow = [9, 6, 8, 3, 9]
# ax.plot(theta, dailyshow, 'b-o')
# ax.plot(theta, colbert, 'r-s')
ax.fill(theta, dailyshow, 'b')
ax.fill(theta, colbert, 'r')
for patch in ax.patches:
patch.set_alpha(0.5)
# FIXME: legend doesn't work when fill is called
# ax.legend(['The Daily Show', 'Colbert Report'])
ax.set_varlabels(labels)
# FIXME: rgrid lines don't appear; works if RESOLUTION is increased.
rgrids((2, 4, 6, 8, 10))
grid(True)
show()
-Tony
On Jun 20, 2008, at 12:16 AM, Curtis Jensen wrote:
No guarantees on when I'll have time, but I'll work on it.
Thanks for the info.
--
Curtis
On Thu, Jun 19, 2008 at 8:17 AM, John Hunter <[EMAIL PROTECTED]>
wrote:
On Wed, Jun 18, 2008 at 2:43 PM, Curtis Jensen <[EMAIL PROTECTED]
> wrote:
Nice. Thanks. I had tried to do something similar, but kept
getting
a curved line between each data point.
Also, I too got errors with a previous versions of matplotlib, but
0.98 works.
If someone were willing to add Radar plots to the matplotlib
functionality, would this be wanted by the users or maintainers?
Yes, certainly. You may want to take a look at the polar
implementation (can you inherit from it?) to reuse as much as
possible. Michael has also written a short guide to developers
working with nonlinear projections
http://matplotlib.sourceforge.net/doc/html/devel/add_new_projection.html
JDH
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