[Talk-GB] Armchair-mapping postcodes (was: B72 is a wrap)
Andy Robinson (blackadder-lists ajrlists@... writes: Great work! How can you tell when you have every postcode and is there some way of checking them against the OS OpenData postcode centroids? Just by being systematic. If you have Chillly's codepoint postcode layer sitting over BING its easy in the editor to assign the postcodes as you see them when adding buildings. http://www.raggedred.net/codepoint/ I see - so you can use your judgement to work out the area of a postcode based on its centroid and the streets and buildings nearby. Since this isn't using any kind of ground survey to check the data, I wonder if it would be a suitable task for a bot? A program making guesses about postcode areas might not be any more fallible than a human doing the same task. Of course it could only be done in areas that had already reached a high standard of completeness, ideally with buildings traced as well as streets. Or, perhaps, the robot could make suggestions which a human would then accept or reject, so that 95% of the area could be covered, with human assistance for the last few tricky bits. -- Ed Avis e...@waniasset.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Armchair-mapping postcodes (was: B72 is a wrap)
Ed Avis [mailto:e...@waniasset.com] wrote: Sent: 15 February 2011 5:24 PM To: talk-gb@openstreetmap.org Subject: [Talk-GB] Armchair-mapping postcodes (was: B72 is a wrap) Andy Robinson (blackadder-lists ajrlists@... writes: Great work! How can you tell when you have every postcode and is there some way of checking them against the OS OpenData postcode centroids? Just by being systematic. If you have Chillly's codepoint postcode layer sitting over BING its easy in the editor to assign the postcodes as you see them when adding buildings. http://www.raggedred.net/codepoint/ I see - so you can use your judgement to work out the area of a postcode based on its centroid and the streets and buildings nearby. It's not that simple. You need to do the ground survey first to get the house numbers and work out which property belongs to which street. Once you know that you can then assign the postcode. All the area of B72 I mapped out has been walked to get the building numbers first. Cheers Andy ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Armchair-mapping postcodes (was: B72 is a wrap)
Andy Robinson (blackadder-lists ajrlists@... writes: http://www.raggedred.net/codepoint/ I see - so you can use your judgement to work out the area of a postcode based on its centroid and the streets and buildings nearby. It's not that simple. You need to do the ground survey first to get the house numbers and work out which property belongs to which street. Ah, right. I thought it sounded too good to be true! Jerry C. also pointed out that house numbers have to be present. So the ground survey is to add the house numbers - or I suppose just addr:street would be sufficient in most cases? - and then the armchair part is putting those together with the code point data to find buildings in a particular postcode. OSM's coverage of streets is much better than its coverage of buildings. Might it make sense to tag postcodes on ways? -- Ed Avis e...@waniasset.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Armchair-mapping postcodes (was: B72 is a wrap)
Ed Avis [mailto:e...@waniasset.com] wrote: Sent: 15 February 2011 5:40 PM To: talk-gb@openstreetmap.org Subject: Re: [Talk-GB] Armchair-mapping postcodes (was: B72 is a wrap) Andy Robinson (blackadder-lists ajrlists@... writes: http://www.raggedred.net/codepoint/ I see - so you can use your judgement to work out the area of a postcode based on its centroid and the streets and buildings nearby. It's not that simple. You need to do the ground survey first to get the house numbers and work out which property belongs to which street. Ah, right. I thought it sounded too good to be true! Jerry C. also pointed out that house numbers have to be present. So the ground survey is to add the house numbers - or I suppose just addr:street would be sufficient in most cases? - and then the armchair part is putting those together with the code point data to find buildings in a particular postcode. OSM's coverage of streets is much better than its coverage of buildings. Might it make sense to tag postcodes on ways? Nope, streets often have more than one postcode for the properties on that street. It's not the street that has a postcode anyway, it's the delivery points for the mail, i.e. the letterbox in your front door. Hence why I only tag the building with the full postcode. Cheers Andy ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] Armchair-mapping postcodes (was: B72 is a wrap)
Andy Robinson (blackadder-lists ajrlists@... writes: OSM's coverage of streets is much better than its coverage of buildings. Might it make sense to tag postcodes on ways? Nope, streets often have more than one postcode for the properties on that street. It's not the street that has a postcode anyway, it's the delivery points for the mail, i.e. the letterbox in your front door. That is true. But given that in many areas we have good streets but not good buildings, there may be value in adding a simplified version of the postcode data in which a way is tagged with the postcode(s) that apply along it. The use case I am thinking of is the common 'enter your postcode' on business websites or over the telephone. Given a postcode you can find the street (or streets) which it corresponds to. This means that a house number plus postcode is sufficient to make the whole address. A simplified tagging of postcode=x;y on a way would let OSM be used to map postcode to street name. It would not be quite as precise as the PAF, giving two possible streets in some cases where there is only one in reality. But it might be useful for small organizations who want to give people an easy way to enter their address, without paying for the PAF data. (Potentially, a web service could offer this lookup and feed back statistics on which streets were chosen, to be used to fix up the OSM data.) By no means should tagging postcode on ways replace the more thorough building- by-building survey with street numbers, but it might be a first step, just as we usually tend to put the street network in first with no buildings and come back for the extra detail later. -- Ed Avis e...@waniasset.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
