[OSM-dev] Ways with 40k nodes, was: osmosis pgsql schema

Shaun McDonald shaun at shaunmcdonald.me.uk
Fri Oct 31 11:04:16 GMT 2008


On 31 Oct 2008, at 10:44, Frederik Ramm wrote:

> Hi,
>
> Florian Lohoff wrote:
>> Its 2^15 because it signed - and yes - somebody managed to get abovE:
>
> This definitely has to stop. We need to (a) find all ways with more  
> than
> a few thousand nodes and break them down, and (b) educate users that
> they shouldn't do such evil things. Imagine the poor sod who opens a
> little rectangle in JOSM just to find he has to wait for ages to
> download 40k nodes! This slows down so many things.
>
> (And what's more, once someone creates a way with 50.001 nodes, no
> bounding box containing even one node of that way will be downloadable
> through the API.)
>
> I know that shortcomings in the renderers still make it attractive for
> mappers to create giant polygons but we cannot allow this to get out  
> of
> hand.
>
> Any comments? JonB perhaps ;-)?

Should we add something to API 0.6 to block ways that have huge  
numbers of nodes.

Looking at the map call, it  would actually be downloadable, as long  
as the bounding box doesn't contain more than 50,000 nodes. This is  
because the 50,000 node check is done after getting the list of nodes  
in that bbox. Then the 50,000 node check happens. Then additional  
nodes outside the bbox for the ways that have a node in the bbox are  
added to the collection. Thus the api can return more than 50,000  
nodes, just the nodes above 50,000 will be for ways outside the  
current bbox.

Shaun

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