[talk-au] Australia "changing coordinates"

Andrew Harvey andrew at alantgeo.com.au
Tue Aug 2 07:37:29 UTC 2016

I found this explanation helpful

On Tue, 2 Aug 2016, at 01:57 PM, Andrew Davidson wrote:
> What to do about it? Unfortunately the changeover to GDA2020 is not 
> going to happen overnight, the plan is for a three year transition 
> starting in 2017. If it did happen overnight then we could just shift 
> all of the nodes in Australia to their new positions can keep on 
> mapping. What's actually going to happen is that the various different 
> organizations are going to switch at different times and the situation 
> for aerial imagery mosaics will be interesting if they aren't 
> retrospectively re-projected (you'll have some places on GDA2020 and 
> others still on GD94). So I'm guessing the approach of wait and see 
> might be the one to take. Obviously if organizations start releasing 
> data in GDA2020 and people start importing it into OSM we're going to 
> have to make the call: move everything to GDA2020 or convert imports 
> back to GDA94? It's only going to be a real issue once we get access to 
> aerial imagery that's in GDA2020 or people get general access to GPS 
> with decimetre accuracy.

If you have suggestions on better ways to handle this within OSM, please
add them as a suggestion for the 0.7 API at
https://wiki.openstreetmap.org/wiki/API_v0.7 Whether this means
including a date together with the coordinates (for correcting WGS84 to
account for drift), or supporting GDA2020 coordinates directly.

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