[talk-au] Why set coast line to nation park or, administrative boundaries?

[Warin]

On 1/4/23 09:50, Graeme Fitzpatrick wrote:
> Don't know if this helps. or makes it worse!

More data = good.

The fact that the data is confusing, to me, simply means that a simple 
assumptions of using the high tide as the boundary for all is a problem.


>
> Had a thought so looked at Gold Coast Council's online city plan, 
> where I know that a National Park touches the shore:
> https://cityplan.goldcoast.qld.gov.au/eplan/property/41NPW429/0/184?_t=property 
>
> compared to what we have
> https://www.openstreetmap.org/edit#map=18/-28.09018/153.45895
>
> Darker green on Council map is NP, bright green is Council Public Open 
> Space, patch of ocean is Council "ground", which we show as being 
> within the Admin Boundary of Gold Coast City based on PSMA Admin 
> Boundaries, but which is also "outside" the Australian "coastline"?
>
> Other spots on the GC show similar, in that there is a discrepancy, & 
> often an overlap, between Council & State boundaries.
>
>

Umm State seaward boundaries should be 3 nautical miles seaward from the 
'coastline' (~5.5 km). I forget if that 'coastline' used is high or low 
tidal stuff.

You should be able to see the OSM state boundary here 
https://www.openstreetmap.org/relation/13056696#map=13/-28.0814/153.5054

Council boundaries should be a lot closer to the coast(which ever one 
you chose)?

>
> On Fri, 31 Mar 2023 at 18:14, Warin <61sundowner at gmail.com> wrote:
>
>
>     On 29/3/23 14:30, Andrew Harvey wrote:
>>
>>
>>     On Wed, 29 Mar 2023 at 14:05, OSM via Talk-au
>>     <talk-au at openstreetmap.org> wrote:
>>
>>         Since the coastline tag is also supposed to represent the
>>         high water mark then I would say that they should be snapped
>>         together (since they then represent the same feature - that
>>         is, the high water mark). This would mean that the boundary
>>         data already in OSM from the government basemaps would just
>>         be their own mapping of the high water mark, and probably be
>>         less up to date or refined as our own.
>>
>>     Exactly. So if anything we should be actively snapping them.
>
>
>     Are there any links to these boundaries linked to the high water
>     mark???
>
>
>     I would have though that CAPAD data would be accurate as it should
>     come from the National Parks people using the gazette.
>
>
>     My trove searches only turned up low water mark stuff - but I only
>     looked in NSW.
>
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