slow rendering of geojson files

[dkerkow]

The global map with all countries showing at the same time is loading very slowly at the moment. Obviously, it is not so much about the filesize but about the rendering of the very detailed blocks and their sheer number. A nice solution could be https://github.com/mapbox/geojson-vt, which cuts geojson in tiles and simplifies them for each zoomlevel, making it way faster to load (everything on the browser).

@danohuiginn do you think you could add that to the map before the Asia release?

[danohu]

The other option is to generate simplified shapefiles on the backend. The frontend can then use either the simplified or the full versions depending on zoom level or number of countries being displayed.

I looked at https://github.com/maxogden/simplify-geojson -- this lets us reduce as much as we like, though making obvious reductions in accuracy. There seem to be plenty of others around, including https://github.com/mbloch/mapshaper and https://pypi.python.org/pypi/visvalingam.

Either way -- we could hack something together by Tuesday, but I think in the long term we'll be better off pushing back the release and working out how to do the shape simplification properly.

[danohu]

In any case -- it may be that the biggest problem is in-browser rendering time, but we also currently load 23MB of map data when somebody opens the front page. I don't think that's a reasonable thing to launch -- i.e. we will need some server-side simplification.