[Talk-us-massachusetts] Stacked address points from MassGIS

[Greg Troxel]

Yury Yatsynovich <yury.yatsynovich at gmail.com> writes:

> Greetings!
> I have a question on combining stacked MassGIS address points (those with
> EXACTLY the same coordinates) for importing to OSM.
>
> Namely, here is an example of 4 MassGIS addresses in Malden that have
> exactly the same coordinates:
> 93 Home Street
> 95 Home Street
> 93-95 Home Street
> 95 Home Street, Unit B

The first question is what's actually right.  Pretty clearly that set is not.

> How would you combine them?
> Aggregate into two separate points (with and without units) which will
> still be stacked after the import:
> -- "addr:street=Home Street, addr:housenumber=93;95;93-95"
> -- "addr:street=Home Street, addr:housenumber=95, addr:unit=B"

Aside from the fact that 93-95 is an address range not an address, and
probably should be rejected for importing, that seems ok

> Or combine all 4 of them into one point? Yet, here I have a problem of
> thinking about combining addresses with and without units.
> Something like
> "addr:street=Home Street, addr:housenumber=93;95;93-95, addr:unit=B"
> doesn't seem accurate -- there are addresses in this point without unit B...

I am not aware of an established tagging scheme.  It seems not ok in osm
to make up such things as part of an import.   So you could ask the
tagging list, and see what's on the wiki, but it seems unlikely that any
such scheme will be supported by nominatim, osmand, maps,me, mkgmap, or
other things.  As part of the import proposal we should explain how our
tag conversion choices lead to good outcomes with most/all of the known
data consumers.

> On the other hand, something like "addr:street=Home Street,
> addr:housenumber=93;95;93-95, addr:unit=B;", although, indicating that some
> of these addresses do not have units (can it actually be tagged with an
> empty string after ";" in addr:unit??), doesn't give a good idea which are
> these addresses.

That seems wrong too.

> Or would you prefer importing stacked points without combing them at all?
>
> Any thoughts on this?

I actually am unclear on whether we should be importing stacked points
at all, or whether we should be less aggressive.  I am not clear on the
value of adding in a separate unit B point when by all accounts nobody
knows where it is separately.  So it seems like not-quite-right data and
noise, and anybody looking for 95B that finds 95 knows to go there and
look, same as if they find 95B in the db.

Plus, anything we don't import can be imported later, but things we wish
we hadn't (long history of issue in imports) is harder.


So what's the real benefit for importing stacked units at all, in terms
of helping map users?
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