[talk-au] suburb boundaries

Darrin Smith beldin at beldin.org
Sat Mar 7 13:14:39 GMT 2009


On Sat, 07 Mar 2009 23:51:35 +1100
b.schulz.10 at scu.edu.au wrote:

> Hi all,
> 
> It's really nice to see suburb boundaries popping up around the
> place, it just makes the map look that little bit more professional.

Yeah it is isn't it, Franc has done some nice work.
 
> There seems to be some naming redundancy in the NSW data though. The
> previous nswgnb import (before my time, don't know the source or
> history of this) placed suburb names all around the place, and now
> the ABS suburb import is repeating the data. An example of this is
> here:
> http://www.openstreetmap.org/?lat=-32.96227&lon=151.65078&zoom=16&layers=B000FTF
> 
> What are people's thoughts about this? Should the data be sanity
> checked for naming consistency then the nswgnb node deleted? Or
> should it be kept incase some renderer doesn't understand the suburb
> relation? Like perhaps it would be easier for the mkgmap devs to keep
> the nodes rather than have them write code to make a node from the
> relation.

You've hit an interesting point here, one I've thought about a few
times without coming to any reasonable answer myself. 

On the one hand we have the case where we leave around we're making
allowances for any program that for whatever reason doesn't support
100% of the OSM data structures.

On the other we're having multiple version of the same data which have
to some how be kept consistent creating more maintenance of the data.

After many years working with a number of databases I've found every
un-necessary duplication of data leads to headaches, but there's
inevitably going to be software that gets out of date and people are
going to expect the data to change for it rather than update the
software :/

I think what the boundaries need (and this is where a spot where it
being a relation comes in handy) is a way to make a centre node, if
the centre node is there then it can be assume it will display the
name of the boundary, otherwise the renders should display their own
boundary. This proposed option seems to be close to that kind of thing:

http://wiki.openstreetmap.org/wiki/Proposed_features/add_center_in_Relation:boundary

Of course then we'd have to get the renderers to recognize that fact on
not render a centre text for a multipolygon with a 'centre' (unless
they already do that?)

(This has the benefit of moving the name display to a place more
appropriate for the suburb rather than the exact centre of the area,
I'm sure we can all thing of suburbs where the demographic centre
isn't the physical centre)

-- 

=b




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