A town is a physical place, so is a building. Ideally we would have both drawn in as polygons but we are happy to live with nodes until they are. A postcode centroid is not a physical object, it's just a reference to something that is (to the extent that we accept a post delivery point has a physical presence). So I don't think we need to draw any line, we just need to apply the logic we have always applied and limit our node and way additions to OSM to physical objects that can be verified on the ground.
Cheers Andy > -----Original Message----- > From: Colin Smale [mailto:colin.sm...@xs4all.nl] > Sent: 31 October 2012 12:54 > To: Andy Robinson > Cc: 'Colin Smale'; talk-gb@openstreetmap.org > Subject: RE: [Talk-GB] Office of National Statistics data > > > Ah, but we are not in the business of adding non-physical stuff just > > because it makes a search work better. If we have something to add > > postcode data to then that's right and proper, otherwise the postcode > > centroid database can be off map and referenced from a separate > > database. > > I don't get what makes postcode centroids different from place=* nodes. > They are also non-physical insofar as you will not find a dot painted on the > ground with an adjacent sign saying "this dot is Townsville". If these nodes > are not for making a search work better, then I don't know why they are > there at all. Naturally, having a place represented by a boundary polygon > would render the node redundant, but until then, the (usually manually > guestimated) centroid of the place is "good enough" and certainly better > than nothing. Or are you suggesting that the place=* nodes be put in an > external DB as well? Where do we draw the line? > > Colin > > > > > Cheers > > Andy > > > >> -----Original Message----- > >> From: Colin Smale [mailto:colin.sm...@xs4all.nl] > >> Sent: 31 October 2012 12:26 > >> To: talk-gb@openstreetmap.org > >> Subject: Re: [Talk-GB] Office of National Statistics data > >> > >> > Colin, it's fine to add the postcode data to a node object (eg a > >> > poi), just don't create a node with just the postcode and nothing > >> > else as this is meaningless. The postcode data we have is not the > >> > information for individual buildings, its just the centroid of the > >> > address polygon which will contain any number of buildings (or post > delivery points). > >> > Thus when using the data its still necessary to do some > >> > interpretation and it's not possible always to know that you are > >> > assigning the right postcode to the right building/delivery point > >> > because we don't know where the boundary of one postcode is against > >> > another for the same street etc. > >> > >> I am guessing that just having the centroid is plenty adequate for a > >> lot > > of > >> reverse geocoding probably including routing, i.e. "where is XX1 3AB" > >> or "take me to XX1 3AB". Obviously it won't cover questions of the > >> form of "what's the postcode for this building" which will require > >> every > > individual > >> building/delivery point to be tagged. > >> > >> As (legal stuff permitting) "importing" the centroids would cover a > >> very popular use case with (IMHO) a quality which is adequate for > >> most people, > > I > >> would not be so quick to dismiss it. > >> > >> Colin > >> > >> > >> _______________________________________________ > >> Talk-GB mailing list > >> Talk-GB@openstreetmap.org > >> http://lists.openstreetmap.org/listinfo/talk-gb > >> > >> ----- > >> No virus found in this message. > >> Checked by AVG - www.avg.com > >> Version: 2013.0.2742 / Virus Database: 2617/5864 - Release Date: > >> 10/30/12 > > > > > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2013.0.2742 / Virus Database: 2617/5864 - Release Date: 10/30/12 _______________________________________________ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
