Unable to access data array inside gv.WMTS tiles

@jsignell @ocefpaf

Working from a notebook…

import geoviews as gv
import holoviews as hv
hv.extension('bokeh')

lon = -121.8144
lat = 48.7767
dx  = dy = 0.01
url   = 'https://mt1.google.com/vt/lyrs=s&x={X}&y={Y}&z={Z}'

extents = (lon-dx, lat-dy, lon+dx, lat+dy)
tiles = gv.WMTS(url, extents=extents)
tiles

I’m trying to get access to the data array and coordinates inside the tiles object so that I can save it to geotif. Not sure if support for this is just built in so my plan was to pull out the data array and save it using rasterio, as suggested here https://github.com/pyviz/geoviews/issues/68.

Not seeing a method that lets me access the array. Maybe there is a hidden one that can be exposed?

[jbednar]

Looks like contextily can be used precisely the way we are using Quest. Since it’s relatively simple to do it this way (grab bounding box, request data separately), there probably won’t be much enthusiasm for doing the work to do it directly in Bokeh, so I’ll close this for now.

[ocefpaf]

I’m pretty sure that a Bokeh WMTS object never brings the underlying image data into Python at all; the JavaScript object just requests tiles from the webserver as needed and displays them in the browser.

Yep.

We do have an example of doing this (http://earthsim.pyviz.org/topics/GrabCut.html), but it uses an external system called Quest to fetch the tiles, paste them together, and select the appropriate region, once we select a region on the visible tiles.

This will probably make our life easier, thanks. For now contextily seems to do the job.