[OSM-talk] Converting buildings from nodes to ways

Dave F. davefox at madasafish.com
Wed Dec 29 21:16:03 GMT 2010


On 29/12/2010 21:13, Dave F. wrote:
> On 29/12/2010 20:17, andrzej zaborowski wrote:
>> Hi Dave,
>>
>> On 29 December 2010 21:04, Dave F.<davefox at madasafish.com>  wrote:
>>> On 29/12/2010 17:30, andrzej zaborowski wrote:
>>>> On 29 December 2010 13:47, Dave F.<davefox at madasafish.com>    wrote:
>>>>> On 23/12/2010 12:10, Laurence Penney wrote:
>>>>>> I've been 'exploding' several building nodes into ways,
>>>>> City centres maps look so much better with polygon ways, don't they?
>>>>>
>>>>> To encourage this practice it would be useful if the R (replicate) 
>>>>> key in
>>>>> Potlatch worked from nodes to ways. It could also copy the history.
>>>> There's no way in the current database schema to copy history from
>>>> nodes to ways.
>>> Hi andrzej
>>>
>>> Could you elaborate on this please?
>>>
>>> If you mean it can't currently be done, then yes, I know, that why I 
>>> was
>>> posting the email.
>>>
>>> If you mean it can't be implemented in the future, then that's a bit
>>> disappointing. As OSM increases it mapping detail it would be a very 
>>> useful
>>> addition.
>> It could be implemented in the future but the request should not go to
>> Potlatch authors because the issue deeper.  So as far as I know the
>> workings of OSM, it'd have to wait to at least API 0.7.
>>
>> Object history is attached to an object.  Currently objects are
>> referenced by id + object type and IDs are not unique accross types
>> (node, way, relation).  So the type is a property of an object, not a
>> property of a revision of an object.  Thus no object can go from one
>> type to another without losing the history.
>
> I'm not sure if non unique ID's would be a problem as the user is 
> selecting specific entities to copy from & to .
>
> Lets take a node element of a hotel that's been edited 4 times.
>
> Someones remaps it as a polygon way & copies the tags & history with 
> the R key.
>
> The new way entity would only have to store the id tags of the node as 
> historic ie "this used to be a node entity with the the id of XYZ123" 
> whilst keeping the id it was given when created.

When I mean 'historic' I mean storing it as a child node within the XML 
data.




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