I want to be able to ascertain the provenance of the figures I create using matplotlib, i.e. to know which version of my code and data created these figures. (See this essay for more on provenance.)
I imagine the most straightforward approach would be to add the revision numbers of the code and data to the metadata of the saved figures, or as comments in a postscript file for example.
Is there any easy way to do this in Matplotlib? The savefig function doesn't seem to be capable of this but has someone come up with a workable solution?
I don't know of a way using matplotlib, but you can add metadata to png's with PIL:
f = "test.png"
METADATA = {"version":"1.0", "OP":"ihuston"}
# Create a sample image
import pylab as plt
import numpy as np
X = np.random.random((50,50))
plt.imshow(X)
plt.savefig(f)
# Use PIL to save some image metadata
from PIL import Image
from PIL import PngImagePlugin
im = Image.open(f)
meta = PngImagePlugin.PngInfo()
for x in METADATA:
meta.add_text(x, METADATA[x])
im.save(f, "png", pnginfo=meta)
im2 = Image.open(f)
print im2.info
This gives:
{'version': '1.0', 'OP': 'ihuston'}