[OSM-talk] Statistics on planet.osm.gz

Frank Mohr f_mohr at yahoo.de
Thu Apr 13 11:24:18 BST 2006


Colin Mackay wrote:
> If you do that you are creating two logical entities for one physical
> entity. If that is the case it suggests that the data model is incorrect and
> needs to be altered. It would be better to be able to create a single way
> that can accept multiple sets of attributes.
> 
> I know this has been discussed before, but I'm going to bang my drum again.
> If the data becomes messy then the overall usefulness is reduced and we are
> all wasting time. I understand that it must be easy for people to put data
> into the system because without that contribution there is nothing. So I
> guess a compromise needs to be reached. Would it be possible to have
> applications, such as JOSM, guide the user to the correct attributes to use
> in certain situations (I know that's a lot of work) by providing a standard
> set in the drop down with a little help text for each item.


just a pointer to a ERD and an example i did some times ago:
http://wiki.openstreetmap.org/index.php/Thoughts_about_Data_Structures

different logical entities for one physical entity are rather common:

as an example look at a overland road crossing a city
the overland road has its name (in my example "B26"),
in the city it also has an additional name ("Wilhelm Leuschner Strasse")
both share the same physical entity.
(other examples: Pilmuir Street/A823; Pittencrieff Street/A994
hope i found the right Dunfermline)

There are also examples, where 2 overland roads share a short segment
(posted that before), sometimes also with parts of city streets

on a large scale map only the overland roads are shown,
on small scale street maps you see also the city street.


frank


		
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