Un sunto piuttosto utile su alcuni ulteriori motivi per cui serve
https://maps.wikimedia.org/ .
Nemo
-------- Messaggio inoltrato --------
Oggetto: Re: [discovery] Differences between osm.org tiles and WMF tiles
Data: Mon, 06 Feb 2017 19:19:18 -0800
Mittente: Paul Norman
Rispondi-a: A public mailing list about Wikimedia Search and Discovery
projects <discov...@lists.wikimedia.org>
A: discov...@lists.wikimedia.org
On 2/6/2017 1:16 PM, Erika Bjune wrote:
Hi Svetlana,
While we do get data from OSM, we run our own tile server called
Kartotherian <https://github.com/kartotherian/kartotherian>, mainly
for the following reasons:
* OSM's infrastructure is fragile and has cache challenges
* Their datacenter is in London, which means latency becomes an issue
* OSM's rendering stack can't scale horizontally well enough to be
sure they could handle our load
* Their map style is not mobile friendly
* We require multilingual and vector tiles, which their stack can't
do (currently)
* We wanted to provide nicer map styling in general
As a developer of both the WMF styles, OpenStreetMap Carto, and many map
rendering components, I can provide some more detail. I'm not a server
admin for either WMF or the OSMF, but I work closely with them.
The default "standard" map on OpenStreetMap.org is a style called
OpenStreetMap Carto (osm-carto). The particular tiles being served on
osm.org (tile.osm.org) are rendered on OpenStreetMap Foundation (OSMF)
resources. Their usage is controlled by the tile usage policy
<https://operations.osmfoundation.org/policies/tiles/>, which would
prohibit their use as a default map on Wikipedia.
Aside from the policy reasons, tile.osm.org is not designed for
Wikimedia's use, mainly because tile.osm.org is designed for providing
mapper feedback, not efficient rendering.
- tile.osm.org is designed to show changes in OSM data minutes after
they were made. The cost of this is that caching is much less efficient,
and more resources have to be used for each map view. Wikimedia doesn't
need minutely updates, and I think right now updates daily. Most
commercial OSM hosts also update hourly, daily, or weekly. This decision
shows up throughout how tile.osm.org is setup, sometimes in subtle ways
- tile.osm.org is not designed for multiple similar styles, e.g. high
resolution "retina" tiles.
- tile.osm.org isn't designed to export static map images, which is an
important WMF use case
- The tile.osm.org rendering stack doesn't provide some WMF-specific
functionality needed, like integrations with Wikidata, etc.
- Parts of the tile.osm.org rendering stack are in maintenance mode and
have no active developers. This is fine if they do what you need, but
would have been a problem for WMF needs
For the record, I do think a deployment for WMF using the same software
as tile.osm.org would have been possible and met the load requirements,
but not have worked with static maps, multilingual maps, and some other
WMF requirements
I feel OpenStreetMap Carto, the style on tile.osm.org, is a good style
when you look at its goals
<https://github.com/gravitystorm/openstreetmap-carto/blob/master/CARTOGRAPHY.md#main-goals>.
Two of the goals are showing the richness of OSM data and providing
mapper feedback. It doesn't have the goal of being a map where you can
layer additional data on top, which is a key WMF use-case. Two osm-carto
policy decisions that would have been a problem for WMF use are the use
of only OSM data whenever possible, and rendering everything in the
language of the region. The first is a problem because it requires
design decisions which sacrifice cartographic quality, performance, and
complexity, particularly at low zooms.
_______________________________________________
Talk-it mailing list
Talk-it@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk-it
