[OSM-talk] Landuse areas etc. abutting highways

[Apollinaris Schoell]

On 4 Oct 2009, at 13:50 , MP wrote:

>> If you don't want to do micro mapping the best approach is to  
>> create a
>> multipolygon relations for the farm and one for the golf course. use
>> the portion of the highway in the polygon as outer way and delete the
>> duplicate ways.
>
> While this may look reasonable, this is IMHO a bad idea.
>
> I've seen once an area where someone made this by sharing parts of
> landuse=residential (the area) with many roads and forests touching
> it. I tried to fix it in JOSM (the lines were very rough and there was
> usable aerial imagery for that area to draw more precise boundary),
> but the mess was too great and I ultimately gave up (tried to move
> stuff from relations to create separate polygon but it just ended up
> as a big mess).
>

if the lines are very rough this is indeed a bad practice because it  
requires complete rework when you start micro mapping. It's just  
better than ways with nodes on top of each other or ways with shared  
nodes on top of each other. no idea if this can be done in Potlatch  
and in Josm it's tricky to select the way you want if the are all  
stacked on top.
option b) is the best for the described situation. but often areas or  
boundaries touch and then the relation is the best.

> Unless current tools improve a lot their multipolygon handling, I
> think this way sharing in multiple multipolygons should be rather
> avoided.
>

Josm is pretty good here. select a way and open the relation from the  
tag window. Even when tons of relations are shown in the relation  
window you will select the correct one. remove a way from there or  
select another way in the main window and add it. It's also possible  
to open multiple relations in parallel. the relation editor improved a  
lot in the last months and I am pretty happy with the current features.

> Martin
>
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