[OSM-talk] Wanted feature for API 0.7 ??

Peter Dörrie peter.doerrie at googlemail.com
Mon Jun 8 15:48:58 BST 2009


2009/6/8 Frederik Ramm <frederik at remote.org>

> Hi,
>
> Peter Dörrie wrote:
>
>> The current renderes wouldn't be able to handle it either and forcing 50+
>> applications to change would be unappropriate.
>>
>
> Why, we're doing that all the time ;-)


Yeah I thought so too, but this was one of the main arguments against my
first try to establish something like this.


>
> There are many unsolved questions here. For example: What happens if parts
> of the "ancient" world transcend your "fourth dimension", e.g. a
> contemporary secondary road uses a few bits of an ancient Roman road. They
> would surely share the same nodes, wouldn't they? But if someone then
> deletes the secondary road (which he downloaded without ever knowing that
> the Roman road also exists because that was shielded from him), he must not
> delete the nodes because they are still used by other objects...


My angle on this is primarily the historical-genetic one. Taking your
example:

1. Brutus Mappus maps this roman long distance road in 100 B.C he tags it
correctly with highway=roman and surface=cobblestone. The road is used in
that form for the better part of the next two millennia.

2. In the 19th century it gets some heavy usage and deteriorates. The local
government decides to build a new road, which uses some of the same vectors
the roman road used so far. The grat-great-great (etc) son of Mappus (John
Maps) splits the road, tagging part of it as highway=disused and others as
highway=construction.

3. The new highway is ready and John tags it as highway=primary

4. The same thing happens several times over until fake Steve finds a
motorway, using some parts of the primary road, using some parts of the
roman road (which by now is not longer visible in the landscape and has been
tagged as historic).

Okay, what does this mean for whom?

Users: The normal user will see a rendering which shows "what is on the
ground". -> Motorway and those parts of the primary road that still exist

Mappers: The normal mapper will see, what is relevant to him. -> Same as
user and some additional tags (oneway, surface, maxspeed, etc.) plus perhaps
those "disused" roads, as they may still be relevant to mapping.

Special interest person (scientist, etc): He gets the possibility of seeing
exactly what he wants to see. The situation in 100 B.C? no problem. Ask the
database about all disused / historic / etc objects? also no problem.

Different object sharing the same nodes over time (and changing them) is not
a problem.



Greetings,

Peter
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