[OSM-dev] Creating 3-d connected network from ways + layer tag

Apollinaris Schoell aschoell at gmail.com
Thu Jul 30 17:05:42 BST 2009


On Jul 30, 2009, at 8:46 AM, Igor Brejc wrote:

> Apollinaris Schoell wrote:
>>
>> On 29 Jul 2009, at 22:05 , Igor Brejc wrote:
>>
>>> Karl Newman wrote:
>>>>
>>>> The topology rules are simple--if the ways share a node, then  
>>>> they are
>>>> connected and it is possible to navigate from any of the connected
>>>> ways to another (subject to turn restrictions, etc.) The layer  
>>>> tag is
>>>> primarily a hint for renderers for proper display of vertically
>>>> separated features. If the data is otherwise, then it is an error  
>>>> and
>>>> should be corrected.
>>>>
>>> Then how do you handle double-decker bridges?
>>> (http://en.wikipedia.org/wiki/Bridge#Double-decker_bridge)
>>>
>>
>> 2 ways with different layer number
>>
> I was asking more about the "sharing/not sharing nodes" stuff  
> between those two ways
>

can't think of a case where they could share a node. only if we start  
to map an elevator between the 2 ways. but then osm needs to extend to  
a 3d model. mapping 3d with elevation tag might be to simplistic....

at the end of the bridge when the 2 ways can merge into one again then  
topology rule applies as outlined by Karl


> Igor
>
>
> -- 
> http://igorbrejc.net
>





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