[OSM-dev] iD creates invalid (?) highway tags

[Andy Townsend]

On 13/10/2015 09:03, GerdP wrote:
> Hi all,
>
> I wonder why iD allows to create ways with e.g.
> highway=primary;service
> or similar combinations?
>

Whilst there are technical things that editors can do (P2's visual 
indication shows that semicolon values are "wrong" is one example), it's 
not really a technical problem.

New mappers that create something like "highway=primary;service" do so 
because they don't really understand what they're doing yet. It's not 
obvious to new mappers that a road called "High Street" needs to be 
split into several sections if part is primary, part residential and 
part something else.  The only way they're going to find out is if 
something that they see before they start mapping explains this (tricky, 
because it's a bit of an information overload if all they want to do is 
add e.g. a node for a POI).

Also, it's not always possible to pick things like this up within the 
editor at all; for example merging a "highway=residential; 
sidewalk=both" with a "highway=residential" that doesn't yet have the 
sidewalk surveyed.  Did the mapper survey the missing sidewalk or merge 
it my accident?

What we're going to have to keep doing in these cases is spotting new 
mappers and helping them when they get it wrong*.  Editing OSM is 
complicated, especially in detailed urban areas or where a previous 
mapper or import was over-heavy on the multipolygons.

Cheers,

Andy

* which a quick scan of http://resultmaps.neis-one.org/osm-discussions 
suggests that you're doing already a _lot_, so thanks very much for that!