What is the furthest distance between two UK buildings that share the same postcode?

I'm not sure how to find this out myself.

closed as too broad by Kersten, Evil Genius, Mapperz Sep 28 '16 at 13:47

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    What GIS software are you using? What have you tried? – PolyGeo Sep 28 '16 at 11:08
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    Welcome to GIS SE. You don't have a lot of info for us to go by. Please see the help guide on how to write great questions. The difficulty with your problem is if you are trying to find it for a particular postcode or for all UK postcodes? What level of accuracy are you trying to obtain(is it the unit level or district level)? and are you interested in the vertical distance between postcodes? – Knightshound Sep 28 '16 at 11:37

You will need postcode unit polygons (should be a free version - premium version is available to public agencies*).

You will need UK buildings (not free but available to public agencies if you are one*).

If you have no money then you can try Open Street Map (OSM) for non-authoritative data.

Then it's just a distance between buildings in the same postcode unit measurement. Probably cycle through them and keep the largest as you go. Then you will have the largest per postcode unit and then you just look for the largest of those.

This is going to be quite intensive and there are strategies you could adopt to reduce the workload here but that's beyond the scope of my answer.


For some context the largest area postcode unit is "IV27 4NZ" in the code point data set which is 443.5 square km. If it were square this would have sides of 21km and a diagonal of 30km. It's unlikely that there is building at each of the far ends of this but your answer is probably less than 30 km.

EDIT I looked at the largest postcode units in QGIS and the elongated shape results in max distance closer to 40km but these are all in the Scottish Highlands with not many buildings. Also, it really depends on what you classify as a building since a bothy or a shed is a building although I doubt they have a postal address i.e. don't have a postcode. So would you count this?

You have a lot to think about if you are serious about answering this question. Still, I hope I have at least given some indication of the order of magnitude your looking at is around 20-30km.

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