[Talk-GB] Postcode centroids
rb357 at cantab.net
Thu Jan 20 23:09:33 GMT 2011
> Please do not just add the centroid to the map. I don't see the value of
> that. I am interested in the experience people gain from using this
> data, for example to add postcodes to an address such as addr:postcode.
I've added a few addr:postcode to my existing addr:* house numbering. In the
vast majority of cases, I've found that the centroid itself isn't actually a
centroid in the geometric sense - but more sort of a "median" house.
e.g. even on a curved road, the "centroid" lies at the position of one of
the houses that the postcode applies to, not at the geometric centroid -
which would be some distance away and make it very tricky to assign
post-codes to addresses.
The following seem quite common in my area;
* Short roads often have just one post code covering every address on the
* Slightly longer roads will often have one post code for one side of the
road, and one for the other.
* Some roads will be split into segments where each address on both sides
of the road have one postcode - then further up the road, each will have a
different one etc.
* Then there are ones with one for each side of the road - and split into
The roads mostly seem to split into segments if there is a convenient
junction splitting up the housing - but sometimes not - and this requires a
bit of educated guesswork sometimes.
What I've done in the past is created a .osm file with my particular
post-code of interest - and then added the file as a new layer in JOSM - so
I can overlay it. I would certainly be interested to use this new site -
when my postcode areas of interest have been loaded.
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