As I mentioned the other day, my team is in Fort Collins this week for a sprint. Damon Burgett and I were sitting together working yesterday and he says, "I keep looking for the inverse of the xy function in mercantile, but it's never there." It's true, the module is missing a function to convert web mercator x and y to longitude and latitude. He wrote it, and some tests that numbers round trip properly through xy and lnglat, then made a pull request. I merged it, tagged it, pushed to GitHub. A minute later Travis-CI had uploaded mercantile 0.11.0 to the Python package index and we were pulling it back into our sprint work through an updated pip requirements file. I love how frictionless Python development and packaging can be now.
I've got limited time for Rasterio and GDAL issues this week. I can catch up a bit in the evenings, but I must prioritize getting extra rest before Saturday's race. Apologies if I don't respond until Monday.