Why are there two compute calls for plot?

[mrocklin]

Anecdotally I find that when I call .plot() on a dataset object that holds dask arrays compute gets called twice. Why is this? I'm curious if this is something that should be resolved.

[mrocklin]

Sorry, I meant plot.imshow()

[rabernat]

My guess is that this is happening because there is first a call to get the bounds on the data (vmin, vmax).

Does the double compute still happen if you specify vmin and vmax in the call to .plot()?

[shoyer]

We should probably call compute() on xarray objects immediately upon entering a plot method. My guess is that this happens because we rely upon coercing with np.asarray() or DataArray.values to get numpy arrays in xarray plotting methods.