[mapserver-users] Base map data for WMS

[Paolo Corti]

> By "pregenerate" I suppose you mean pre-download from the osm servers?
> This in the general case is prohibited by osm's TOS :
> http://wiki.openstreetmap.org/wiki/Tile_usage_policy

Yes, I am referring to the possibility to do the "seeding" of the
tiles, for example, referring to MapProxy, look at the mapproxy-seed
command [1].

Looking at the link you sent, the sentence "Bulk downloading is
strongly discouraged. Do not download tiles unnecessarily." seems to
prohibit this use case, so you are definitely right. Thought, this
would be seem prohibited just for zoom levels >= 17:

"In particular, downloading significant areas of tiles at zoom levels
17 and higher for offline or later usage is forbidden without prior
consultation with a System Administrator. These tiles are generally
not available (cached) on the server in advance, and have to be
rendered specifically for those requests, putting an unjustified
burden on the available resources.
To avoid having your access blocked, please discuss your requirement
with system administrators either via their wiki pages or on the IRC
channel prior to starting."

In any case, as supposed in my previous email, it is not feasible to
seed the whole OSM on common cases normal sized hardware (unless you
want just to display maps to low zoom levels): on the OSM own servers
they are not caching it for zoom levels >= 17 and I guess they have a
very large infrastructure.
But, could still be a viable approach for smaller datasets coming from
existing WMS that do not prohibit this kind of use.

thanks for pointing this out ;)
P


[1] http://mapproxy.org/docs/1.3.0/seed.html


-- 
Paolo Corti
Geospatial software developer
web: http://www.paolocorti.net
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