this will be a major improvement but a major change. Currently SpatialImplicit indices can accept either a W or a pandana.Network (which have different arguments). It's very easy to make a pandana-backed Graph, so these will now only accept Graphs. The first step is wrapping the network-->graph logic into a little utility function. That could live in lib, like the xarray builder, but also might make sense to move more of the network stuff into spopt. Any thoughts @jGaboardi @martinfleis