[talk-au] suburb boundaries

[Ken Self]

Unfortunately I've found that the ABS data that the data is not as good as
it ought to be. Many nodes that should be shared are not coincident and in
many cases a vertex node for one boundary has no corresponding node on the
"straight through" boundary. And in some cases the vertex node is not quite
on the adjacent way or the ways cross over.

I'm finding that as often as not I have to "join node to way" rather than
"merge nodes" to resolve the boundary intersection

Ken

> -----Original Message-----
> From: Michael Collinson [mailto:mike at ayeltd.biz]
> Sent: Wednesday, 19 September 2012 7:50 PM
> To: talk-au at openstreetmap.org
> Subject: Re: [talk-au] suburb boundaries
> 
> 
> FYI, Franc was kind enough to let me have a copy of his original Perl
> import script.  Email me if you want a copy.  However, and I 
> think Franc 
> would agree, I understand it has really been superceded by the 
> capabilities of ogr2osm.  Emilie Laffray said to me in email, 
> "If it is 
> done properly (and data is good), ogr2osm would remove 
> duplicate nodes, 
> merges ways etc... A little inspection of data should provide 
> us this."
> 
> On the discussion of whether it is actually a good idea, my mild
> suggestion, (I am no longer based in Australia), is that 
> OpenStreetMap 
> schema and so on is becoming stable enough to think about having 
> separate layers outside the main database.  This might well suit the 
> suburbs boundary case. Perhaps one as an as is "official" 
> layer and one 
> as a community-edited version.
> 
> 
> Mike
> 
> 
> On 19/09/2012 11:17, Andrew Harvey wrote:
> > Hi Ken,
> >
> > On 19/09/12 11:57, Ken Self wrote:
> >    
> >>> In doing a manual load I am ensuring the boundaries share common
> >>>        
> > boundaries
> >    
> >> with one another and the multipolygons close off properly.
> Those are
> >> pretty much impossible to do with an automated load. Even a few
> >> manual errors creep in but they are easily fixed.
> >>
> >> As I understand it from the ABS website
> >> 
> http://www.abs.gov.au/ausstats/abs@.nsf/0/a9421cdfb258e4a4ca2570ad008
> >> 18509?o
> >> pendocument they are supposed to be the gazetted boundaries
> >>      
> > ... that document is for the 2006 census boundaries.
> >
> > For the 2011 ASGS, the Non-ABS structures data is at
> > 
> http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/1270.0.55.003July%
> > 202011?OpenDocument
> >
> > With the documentation at
> > 
> http://www.abs.gov.au/AUSSTATS/subscriber.nsf/log?openagent&1270055003
> > 
> _oct%202011.pdf&1270.0.55.003&Publication&469CDA45CE2B94CCCA257937000D
> > 966F&&July%202011&31.10.2011&Previous
> >
> > it states that the LGA boundaries which form part of the ASGS 2011,
> > "are an ABS approximation of officially gazetted LGAs as defined by 
> > each State and Territory (S/T) Local Government Department."
> >
> > Which is good enough for most purposes, and a good starting
> point for
> > later corrections.
> >
> > I suppose that raises an interesting point, that in true
> OSM spirit if
> > on the ground data indicates an area is LGA X (eg. street sign
> > branding), but the "official" gazetted boundaries say 
> otherwise, OSM
> > should primarily contain what's on the ground, rather than the
> > "official" one.
> >
> > Again quoting from that document, the suburb boundaries which form
> > part of the ASGS 2011, "are an ABS approximation of localities 
> > gazetted by the Geographical Place Name authority in each State and 
> > Territory (S/T). Since 1996 these boundaries have been 
> formalised for
> > most areas of Australia through a program coordinated by
> the Committee
> > for Geographical Names in Australasia (CGNA) under the
> umbrella of the
> > Intergovernmental Committee On Surveying and Mapping
> (ISCM). SSCs are
> > built from Statistical Area Level 1 (SA1) that, singly or in
> > combination, form an approximation of Gazetted Localities."
> >
> >    
> >> The question is what to use as a definitive source for corrections
> >> that is ODBL compliant. I've found some maps on 
> >> 
> http://www.vec.vic.gov.au/publications/publications-maps.html#5 but
> >> not sure if we can use them to make corrections in OSM to the ABS
> >> boundaries.
> >>      
> > No you cannot gather information from those maps and
> transfer it into
> > OSM.
> >
> > Those maps are Copyright All rights reserved. And the
> golden OSM rule
> > is don't copy from other maps unless they are released under a
> > compatible license.
> >    
> 
> 
>