OpenStreetMap
Triskaidekaphobia in Dublin
Posted by DeBigC on 23 August 2021 in English. Last updated on 24 August 2021.I map a lot of buildings in northern Dublin City. I also interrogate housenumber interpolations, view mapillary for little peeks of the housenumbers that aren’t blurred, and do my own StreetComplete captures to add as many address details as possible. Lately I have noticed something, born from a concern that I was doing something wrong, or making a mistake.
In a few housing developments around Dublin housenumber=13 doesn’t exist. I have heard of such indulgences before, for example some airlines dropping row 13 from seating plans, or the Irish car registration authority famously dropping its numeric system in 2013 to avoid the unluckiest of car numbers.
So out of curiousity I hit OverPass Turbo and launched a series of queries like this into the existing housenumbers. I couldn’t do loads of these so I thought that maybe 19 would be a sufficient sample (42,000 building objects) to make comparisons and establish patterns.
I plotted these values and observed, as expected, that number 1 is most frequent, since short streets and long streets all seem to have a #1. The numbers after #3 have a simple arithmetic decline. An unexpected result was that there are a few more #3s than #2s, but I will return to that in a comment if anyone wants to ask me :)…. Back to #13! There were around 60 less than I expected. This means #13 doesn’t appear so much as it should, even taking the decline in numbers and the finiteness of space for houses to be built into account.
I took this a stage further. I used an R-square test to establish if the quicker decline from #12 to #13, and slower decline from #13 to #14 are significant, in other words - is there something else going on with this blip in the decline pattern other than chance. And with an R-square value of .99 it seems there is indeed something going on!
All joking aside the lack of #13 may not be down to superstition, and may rest on a dominant architectural tendency to place an even number of houses on a site. It could be that mappers are superstitious, though I doubt it. So while this itself is not proof I give you Ashbook housing development in Dublin, where #12 and #14 are present but #13 is not.
Good Luck!
PS talk about this on twitter
Discussion
Comment from b-unicycling on 23 August 2021 at 19:29
Very interesting, thanks for all the effort!
Comment from philippec on 23 August 2021 at 19:49
Are the even numbers also to the right of the street if you have your back to the town hall ?
Comment from philippec on 23 August 2021 at 19:52
You mean “blurred by mapillary” ? People can also have good reasons to blur their street number or their names.
Comment from VictorIE on 23 August 2021 at 20:32
So that’s why we have The Avenue, The Close, The Court, The Crescent, The Green, The Grove, The Haven, The Lawn, The Mews, The Rise, The Road, The Square, etc. as actual names within a named estate (instead of Ballymore Avenue, Ballymore Close, Ballymore Court, Ballymore Crescent, etc.)
Presumably estate agents don’t want to sell house number 13, as they think people won’t buy it.
Developers don’t want to spend load of money on signs, so they get standard signs instead of custom signs.
Comment from philippec on 23 August 2021 at 20:35
I grew up in a nr 13. It ended catastrophically.
Comment from DeBigC on 24 August 2021 at 07:41
@b-unicycling, you are welcome
@philippec there are no formal rules in Ireland for numbering. Some streets are odds/evens and others are purely sequential. There is no focal point either, numbers can progress east, or west, or both (for an example look at the streets around Oxmantown Road). Yes, I mean Mapillary and I am not a big fan of blurring. It holds OpenStreetMap back a good deal.
@VictorIE I think you are right, the house vendors don’t want any negativity sometimes, and so slip out of #13
Comment from SK53 on 26 August 2021 at 11:14
In the UK the aversion to #13 can be seen to largely arise post-WW2.
Most streets built prior to WW2 will have a number 13, although often this is now 11A, 15A or similar. Social housing dropped #13 a lot later than speculative private housing as I know estates built in the late ’70s which still had #13.
Any builds post-1980 exclude #13 and usually have a clever break in the runs of houses so that it is not obvious that one number is missing. (A prediction of this is that #12 & #14 or #11 & #15 are more likely to be end terraces (or the appropriate side of a semi detached house).
I think culturally the aversion to #4 in East Asian cultures is even more noticeable.
Comment from mmd on 26 August 2021 at 15:08
https://overpass-turbo.eu/s/1aEi might be good to fetch all addr:housenumber in Dublin along with their count, all in a single query.
Comment from jidanni on 8 September 2021 at 17:06
https://www.jidanni.org/geo/house_numbering/index.html#fearoffour
Comment from VictorIE on 8 September 2021 at 17:30
https://www.jidanni.org/geo/house_numbering/index.html#fearoffour
“Perhaps the whole country’s addressing is purposely disorganized, for National Defense purposes?” - that sounds familiar in Ireland. :)
Before Eircodes over 35% of addresses in Ireland were non-unique, where there is no house name or number. This primarily applied to rural areas and smaller towns.
During World War 2, all directional signage was removed from roads. There was a strong suspicion that many were put back in the wrong place, until they were finally all replaced in the 2000s.