[OSM-talk] Mapnik tileset coherency issues
tom at compton.nu
Thu Oct 18 14:37:34 BST 2007
In message <220CB213-644D-446B-A291-D96CCBE3A847 at remote.org>
Frederik Ramm <frederik at remote.org> wrote:
>> What I mean is, say a tile x,y,z is dirty and needs to be
>> rerendered. You would include adjacent tiles on a given z , but
>> also on lower z levels (say a dirty tile x,y at zoom level 12,
>> would also mean all tiles contained by tile x,y at subsequent zoom
>> levels 13,14 ... would be considered dirty in the same job). Could
>> you render this batch of tiles than into a cache, before committing
>> the whole batch to the live tileset, thus ensuring more consistency ?
> My understanding is that mapnik is so fast at rendering tiles that
> rendering a whole tileset (level 12 and everything below it) could be
> done in a time short enough as to not require any extra "buffering";
> the inconsistent state would probably only exist for a few minutes.
The problem is that at busy times we can already have 100,000 tiles
queued for rendering, which is several hours worth. Automatically
adding surrounding tiles and inferior/superior tiles will obviously
add to that.
Tom Hughes (tom at compton.nu)
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