[OSM-dev] OpenStreetMap Cartographic: A client-side rendered OpenStreetMap Carto
ndrw6 at redhazel.co.uk
ndrw6 at redhazel.co.uk
Tue May 26 13:46:54 UTC 2020
On 26/05/2020 13:26, Christoph Hormann wrote:
> As Joseph has hinted when it comes to accurate rendering for precise
> mapper feedback without unintentional incentives at the lower zoom
> levels there are other options based on pre-rasterizing the data which
> would still allow using the benefits of client side styling. I have
> demonstrated that in the past.
Rasterization is a data generalization technique too. Yes, in some cases
it leaves no artifacts at all but that's not true in a general case and
almost never true on mobile platforms. It is a viable solution but to
make it work well the style should not use borders or bake in
antialiasing (i.e. leave that to the client code).
I am concerned about something else - even with polygon generalization
in place, the performance is not great. Zooming/panning is rather slow
on my not so weak PC - the map would be unusable on a mobile device or
at best it would be draining the battery quickly.
I've been looking into the code and I couldn't find anything related to
polygon generalization. Where is it done? If it happens automatically in
the Mapbox GL renderer that's too late - all the cost of preparing
tiles, transmitting them, processing them in the client has already been
incurred. Displaying data via WebGL is probably the cheapest part of the
processing chain.
ndrw
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