[OSM-dev] OSM for Retina and high-pixel density devices

[Michael Meier]

On 01/28/2015 01:32 AM, Paul Norman wrote:
> It would be up to the system administrators and OWG to decide if they
> wanted to deploy retina tiles. Deploying a second set of tiles would
> increase the CDN cache miss rate, increase the rendering required, and
> significantly increase the disk space required for tiles. The last is
> likely to be particularly significant as I don't believe the machines
> have the free disk required to more than double the cache.

It might be possible to just render/cache the HD tiles, and then scale
them down on the fly for non-HD requests - only one set of tiles would
need to be stored/cached, at the cost of some wasted cpu-cycles for the
scaling.

However, in addition to the problem of limited resources, I don't think
the style is ready yet. Though there has been a lot of progress lately,
the openstreetmap-carto-style has many symbols, and many still aren't
SVG and thus are not "HD ready" - they look really ugly in HD tiles. I'm
unaware of a public demo-instance, so this is mine, showing how the
openstreetmap-carto-style currently looks like when rendered in HD:
https://osm.rrze.fau.de/testhd.html
(this is really just tirex with scalefactor=2.0, tilesize=512,
buffersize=768 set on a checkout of openstreetmap-carto)
-- 
Michael Meier, Zentrale Systeme
Friedrich-Alexander-Universitaet Erlangen-Nuernberg
Regionales Rechenzentrum Erlangen
Martensstrasse 1, 91058 Erlangen, Germany
Tel.: +49 9131 85-28973, Fax: +49 9131 302941
michael.meier at fau.de
www.rrze.fau.de