Canvas plot with ratio="autot" results in interaction errors

[scottwittenburg]

When doing canvas.plot() using ratio="autot" and canvas.interact(), the longitude values given by the interaction popups are increasingly erroneous as you move away from center (longitude = 0) of the plot.

This was recently raised as an issue on vcs-js, see here. It can be reproduced as follows:

import vcs, cdms2

cltfile = cdms2.open(os.path.join(vcs.sample_data, "clt.nc"))
clt = cltfile("clt")
canvas = vcs.init(geometry={'width': 800, 'height':600})
box = canvas.createboxfill()
canvas.plot(clt, box, ratio="autot")
canvas.interact()

See the issue linked above for more details and screenshots.