[talk-au] Victorian Vicmap Address Import Proposal

[cleary]

In a previous post on this topic, I suggested it was important to include 'suburb' and postcode in the proposed address import because of my prior experience and discussion with other mappers about problems with Nominatim.

However, after reading Andrew Davidson's comments, I have checked some locations that I considered vulnerable to incorrect addressing. I was impressed to find that the only incorrect ones were those for which a suburb had been included in the address node but suburb boundaries had subsequently been changed so that the old (now incorrect) address continues to prevail whereas, without that tag in the node, the correct address would have been shown by Nominatim.

So I withdraw my previous comments and defer to Andrew Davidson on this point.





On Thu, 20 May 2021, at 8:00 PM, Andrew Davidson wrote:
> On 19/5/21 2:48 pm, Andrew Harvey via Talk-au wrote:
> 
> > 
> > 2. Should we also import `addr:suburb`, `addr:state` and `addr:postcode` 
> > tags? I'm proposing we do.
> 
> Please don't do that. Now that we have a complete set of admin_level 10 
> boundaries in Australia addr:suburb is now redundant.
> 
> > Given postcode regions aren't mapped, then adding these to the address 
> > should be very helpful.
> 
> Postcodes can be added once to the level 10 admin boundary or as a 
> separate postal_code boundary if they don't align.
> 
> > `addr:state` is less important given these addresses fall within the 
> > Victoria state admin boundary already. The wiki touches on this saying 
> > "A few mappers consider higher-level tags, or even addr:city=* as 
> > redundant, since they could be calculated from the respective boundary 
> > relations they are contained in (if present and valid). However, such 
> > practice has severe disadvantages and can lead to wrong results."
> 
> If you read the explanation on the talk page this does not apply to 
> Australia because we have contiguous postal areas.
> 
> > Either way, I don't think it matters too much, but since it's not 
> > harmful to include, and might provide some benefit, then we may as well 
> > include `addr:state`?
> 
> It is actually harmful because you have to maintain the same piece of 
> information in thousands of places. Not only that having multiple 
> sources of information seems to confuse Nominatim. On the other hand 
> adding it has no real benefit, so I would suggest that you don't import 
> anything beyond the street name.
> 
> > 3. `addr:suburb` vs `addr:city`.
> 
> The addr:city is for countries where the postal address has the concept 
> of a postal city. As we don't have that in Australia then we don't need 
> to have this tag.
> 
> > 
> > Both tags are in use within Australia. According to taginfo 
> > (https://taginfo.geofabrik.de/australia-oceania/australia/search?q=addr%3A 
> > <https://taginfo.geofabrik.de/australia-oceania/australia/search?q=addr%3A>) 
> > within Australia addr:suburb occurs 521 ,671 times and addr:city 562,542 
> > times.
> 
> About 99.99+ % of those addr:city are from the Brisbane address import 
> and I would view that as a mistake rather than a reason to perpetuate 
> this elsewhere.
> 
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