[Talk-ca] duplicate address data

[Gerd Petermann]

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.










 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-ca/attachments/20150326/282a010b/attachment-0001.html>