[Talk-GB] Postcode centroids

Chris Hill osm at raggedred.net
Fri Jan 21 11:34:55 GMT 2011

On 20/01/11 23:09, Richard Bullock wrote:
>> 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 street
> *    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 segments.
> 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.
All very useful observations. What is your postcode area (e.g. HU) so I 
can load it?

Cheers, Chris
user: chillly

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