[Talk-ca] duplicate address data

[john whelan]

Basically the CANVEC data imports need cleaning up.  I think there were ten
different versions, the most common I think is 7.  Unfortunately some
mappers locally removed the CANVEC tags from the data if they touched it or
even on the import as they didn't think it was important.  Sometimes
addresses were imported with a CANVEC tag, sometimes not.  Due to funding
cutbacks the CANVEC data is no longer exported in OSM format.

Also there was some original mapping done from low resolution satellites,
Yahoo I think provided the images so some roads were mapped about 100
meters from where they should be, where highways had been mapped the CANVEC
imports were sometimes used and sometimes not.  In Ottawa we took a local
decision to delete all the roads above service roads and replace them with
CANVEC imports because of the data quality issues of the existing road
network and that was some years ago.

Unfortunately in Canada we have fewer mappers per kilometer of highway than
in Germany and the CANVEC imports were very useful.

The clean up solution I would suggest would be to delete all address
information with a CANVEC tag on it then import only CANVEC 10 which is the
latest version but that's a lot of work but the end result would be clean.
It might also hit problems as the address information would follow the
CANVEC highways rather than those highways mapped in other ways but it
would only be the address information and the road network would remain as
it is.

Cheerio John

On 26 March 2015 at 14:54, Gerd Petermann <gpetermann_muenchen at hotmail.com>
wrote:

> Hi list,
>
> I am one of the developers of mkgmap, see also
> http://wiki.openstreetmap.org/wiki/Mkgmap
> and
> http://gis.19327.n5.nabble.com/Mkgmap-Development-f5324443.html
>
> During the last weeks I've enhanced the support for
> the evaluation of addr:interpolation ways or more general
> the evaluation of addr:housenumber, addr:street and so on
> to improve the address search in Garmin devices for maps
> based on OSM data.
>
> I live in Germany and I am not very familiar with the address
> schemes used in North America.
>
> It turned out that data in Canada is very special because of the
> CanVec imports. I find a huge amount of addr:interpolation
> ways that seem to make no sense, often those are
> duplicated with identical or nearly identical points
>
> Example: The ways
> http://www.openstreetmap.org/way/99649911
> and
> http://www.openstreetmap.org/way/83504524
>
> One has source=NRCan-CanVec-7.0, the other source=CanVec 6.0 - NRCan
> Is there a good reason for this redundancy?
> If not, what is the best way to remove these duplicates?
> I can think of different ways:
> 1) keep only the eldest entry
> 2) keep only the youngest entry
> 3) keep the older and add a note that the data is confirmed by
> NRCan-CanVec-7.0
>
> Second problem that occurs very often:
> http://gis.19327.n5.nabble.com/weired-housenumbers-in-Canada-tt5835196.html
>
> The example still exists:
> http://www.openstreetmap.org/way/133338396
> A long addr:interpolation way connecting two points which both have
> addr:housenumber=5.
> If that data is correct, what information does it offer?
> I can only guess that along this long way one can find a house with
> number 5. Or does it mean that the house is in the middle?
> Or is the whole ground along this road "20th Sideroad 5" ?
>
> And what does it mean when multiple addr:interpolation ways
> exist connecting points with equal addr:housenumber,
> like here:
>
> http://www.openstreetmap.org/way/133570749#map=18/45.68026/-80.03331&layers=N
> Where is  Bear Hug Lane 10 and why are there so many addr:interpolations
> ways for it?
>
> Any help is welcome.
>
> Gerd
>
> P.S.
> The program mkgmap in the housenumber2 branch creates a log file that
> reports the problem cases in a format like this:
> "found additional addr:interpolation way with same meaning, is ignored:
> 1st Avenue http://www.openstreetmap.org/way/99649911 127..123, step=2"
> it would be easy to change that if needed.
>
>
>
>
>
>
>
>
>
>
>
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>
>
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