[Matplotlib-users] Saving figure with an image and a time axis as an EPS shifts image relative to other plot features

[Chad P. <par...@gm...>]

Hello everyone-

I'm a new Python/Matplotlib user, but I have quite a bit of plotting
experience with octave/matlab and gnuplot. So, I apologize in advance if my
python style is terrible and if I give you all the wrong information!

I'm having a problem saving figures that contain images as eps files when
my x-axis is a date/time axis. The trouble is that in the resulting eps
file, the image data is shifted relative to the axis. I've attached two
images as an example. In the .png file the alignment is correct and in the
eps file it's not. The png is also nearly identical to what I get when I
plot to the screen. The script I wrote to generate these plots is at the
end of this message.

It's worth noting that the two output images are identical if the x-axis is
simply numerical and not a time series.

I'm using python 2.7.3 and Matplotlib 1.1.0

Some Google searches dug up this old thread, however, the shift that I'm
experiencing seems to be much greater, so I don't know if it's related:
http://old.nabble.com/Saving-as-eps-file-shifts-image--td29232680.html

Can anyone help me solve this?
Thanks in advance,
--Chad


Here is a minimal script that I used to generate these plots:

import matplotlib.pyplot as plt
import matplotlib.dates as dts
from matplotlib.colors import LogNorm

imgData = [[1.0/x + 1.0/y for x in range(1,100)] for y in range(1,100)]

tMin=dts.epoch2num(1343947266)
tMax=dts.epoch2num(1343947266+100)

axImg=plt.subplot(111)
axImg.imshow(imgData, norm=LogNorm(),extent=(tMin,tMax,1,100),\
                interpolation='none', origin="upper")
axImg.xaxis_date()
axImg.set_aspect('auto')

plt.savefig("imageshift.png")
plt.savefig("imageshift.eps")