[talk-au] suburb boundaries
Hello all, I would like to ask what the status of the suburb boundaries is? https://wiki.openstreetmap.org/wiki/Import/Catalogue/ABS_Data user pnorman (on IRC) has offered to import this data if nobody knows how to do it___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] National borders (was: import of state borders?)
Hi 2012/9/18 Ian Sergeant inas66+...@gmail.com If I understand correctly, the differences should only correspond to the amount that our coastline differs from the low water mark? Are we missing parts of the true coastline, is our coastline just inaccurate do you think? Well, to me there are two major reasons for differences between the coastline in osm and the baseline used to compute the boundary: (a) osm's coastline definition as the high water mark vs. the baseline defintion as the low water mark. Obviously the difference is quite small at cliffs and increases a shallow beaches. But the biggest difference is caused by something off the coast inundated at high tide but showing at low tide - e.g. high parts of a reef. (b) Smaller bays are cut off straight. These are not included in the list of points [1], in there are only the additional larger sections. I've tried to illustrate this a bit generating an image in QGIS [2]. It combines OSM with the data from [3] to show the situation. I'd be surprised if there was any definitive low water mark data for the entire coastline. I don't know how it has been generated but I'm afraid there is one. As this directly translates into the extension of the territorial waters etc. there's quite some incentive to have it defined. Should we start with a simpler section, like NSW? This probably wouldn't really help much as it doesn't really solve the problem. Last night I have spent some time on the topic and would currently suggest the approach to simply use what's there. Use coastline from OSM and combine with the straight sections from [1]. For both a 12 nautical mile buffer can be computed in QGIS and combined. This will not be accurate as it neglects the reefs etc. But it's probably the best we can get. BTW I haven't checked yet, if there are reefs mapped in OSM. If so they could perhaps be added into the process. Michael [1] http://www.comlaw.gov.au/Details/F2006L00525 [2] https://dl.dropbox.com/u/1222615/coastline.png [3] https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILScatno=63565 ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] suburb boundaries
I've been manually loading up the suburb and LGA boundaries in Victoria from ABS 2011. Figured that would be quicker than waiting for everyone to reach a consensus on how to automate it and means it gets done properly 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/a9421cdfb258e4a4ca2570ad00818509?o pendocument they are supposed to be the gazetted boundaries There are a few errors in the boundaries but I think it's easier to fix those once the main load is done. After that I'd suggest it's a manual effort to make any further changes. It's not something I'd want to do again from scratch. 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. Anyway - cross that bridge when we get to it. Cheers Ken On 18 Sep 2012 16:40:02, Ian Sergeant inas66+...@gmail.com wrote: Hi Anthony, I don't think not knowing how to do it is the issue. More to the point is that we imported the 2006 ABS data, and it may have caused more problems that it solved. The boundaries correspond to ABS statistical regions. They aren't necessarily suburb boundaries, nor towns, nor governed areas. If we import them again, what do they represent? Do we update the manually? If the ABS release a newer data set do we replace the old? If so, is it even reasonable to import data we don't want to modify? Every data consumer would like to see more data in the OSM database to consume. However as data maintainers we have to balance their needs with our ability to manage an incredibly voluminous import and keep it maintained and accurate within the OSM database. We've removed the ABS2006 data, and it did a fair bit of damage in doing so. I'd like to think we had learned the lessons of that before embarking on the next one. Feel free to initiate a discussion. Ian. On 18 September 2012 16:24, Anthony pan...@live.com wrote: Hello all, I would like to ask what the status of the suburb boundaries is? https://wiki.openstreetmap.org/wiki/Import/Catalogue/ABS_Data user pnorman (on IRC) has offered to import this data if nobody knows how to do it ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Aligning steets
I've seen it flatly stated that Australia didn't have any real mini-roundabouts. That may have been true once, but the last few new roundabouts I've seen built near me have all been either true mini roundabouts (nothing but paint) or a couple where there is a raised centre concrete disc, but it's only raised about a cm, and is fully traversable. I'm not sure why they've started appearing. Stephen On 15 September 2012 22:26, Nick Hocking nick.hock...@gmail.com wrote: Hi Brett, You've just said a *really controversial phrase (mini roundabouts). In Australia there is a *LOT* of history surrounding these things. I do have a definite opinion on them but I reckon it would be best (if not unbearably tedious) for you to read the many vitiolic posts on this subject on talk-au. Cheers Nick ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
