[talk-au] Talk-au Digest, Vol 109, Issue 22

Sat Jul 30 19:58:39 UTC 2016

On 30 Jul 2016 10:34 PM, "Timothy Ney" <neyfamily1 at gmail.com> wrote:
>
> I am a professional surveyor with knowledge of the changing coordinates.
What you are referring to is the adoption of MGA2020. To be implemented 1
January 2017. As mentioned below the new system we consider plate drift, at
approximately 7cm per year. The most important element is that the new
system will be earth centred using the ITRF whereas AMG66, AMG84 and GDA94
were plate centred. On 1 January 2017, all physical marks will be given a
new set of coordinates, up to about 1.6m different to GDA94. For a while,
two systems will run similtanously, the new plate and earth centred
systems. Eventually, the plate centred coordinates will be phased out. It
is expected that an adjustment will be conducted each year, and coordinates
updated.

I'm struggling to find any information about software support of GDA2020.
The icsm FAQ has no mention of this, and I can't find anything relevant re
GDA2020 and the widely used open source libraries like proj4 and GDAL.

Can anyone help illuminate?

Nyall

>
> Given that most modern GPS systems in phones, cars etc can only achieve
accuraries of 1-3 metres, it will be quite some time before old data will
no longer align with the GPS. It should also be noted that most systems
including Google use the ITRF, or some reference to it.
>
> In summary, the impact to most internet mapping systems will be minimal.
Even for surveyors, who is the coordinate information, the update will have
minimal impact, as we tend to work in small areas, where coordinates are
relative only. The big players are those doing broad scale mapping and
other regional wide work. See here for more information.
>
> www.icsm.gov.au/gda2020/faqs-2.html
>
>
>
> On Sat, 30 Jul 2016 at 10:03 PM, <talk-au-request at openstreetmap.org>
wrote:
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>>
>> Today's Topics:
>>
>>    1. Australia "changing coordinates" (Andy Mabbett)
>>    2. Re: Australia "changing coordinates" (Warin)
>>    3. Re: Australia "changing coordinates" (Andrew Harvey)
>>    4. Re: Australia "changing coordinates" (Warin)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Fri, 29 Jul 2016 13:40:45 +0100
>> From: Andy Mabbett <andy at pigsonthewing.org.uk>
>> To: talk-au at openstreetmap.org
>> Subject: [talk-au] Australia "changing coordinates"
>> Message-ID:
>>         <CABiXOE=95mWdWn1P4SvG3ekrRktk0PEvhGNqZ=
c2vgxrbHHEcA at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> See you when you reach England ;-)
>>
>>    http://www.bbc.co.uk/news/technology-36912700
>>
>> But seriously: what impact might this have, on OSM?
>>
>> --
>> Andy Mabbett
>> @pigsonthewing
>> http://pigsonthewing.org.uk
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Sat, 30 Jul 2016 08:40:41 +1000
>> From: Warin <61sundowner at gmail.com>
>> To: talk-au at openstreetmap.org
>> Subject: Re: [talk-au] Australia "changing coordinates"
>> Message-ID: <0485644d-097a-3de6-5bd2-71d49c034f60 at gmail.com>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>>
>> On 7/29/2016 10:40 PM, Andy Mabbett wrote:
>> > See you when you reach England ;-)
>> >
>> >     http://www.bbc.co.uk/news/technology-36912700
>> >
>> > But seriously: what impact might this have, on OSM?
>> >
>> Very little!
>>
>> The change, distance wise, is upto 1.5 metres, well within commercial
>> GPS uncertainties.
>>
>> The change is to the datum. How this will work out with future global
>> datums we will have to wait and see.
>>
>> In another 30 years there will probably be another change of around 1.5
>> metres again.
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Sat, 30 Jul 2016 13:57:31 +1000
>> From: Andrew Harvey <andrew at alantgeo.com.au>
>> To: talk-au at openstreetmap.org
>> Subject: Re: [talk-au] Australia "changing coordinates"
>> Message-ID:
>>         <
1469851051.2451056.680960441.20F38439 at webmail.messagingengine.com>
>> Content-Type: text/plain
>>
>> On Sat, 30 Jul 2016, at 08:40 AM, Warin wrote:
>> > The change, distance wise, is upto 1.5 metres, well within commercial
>> > GPS uncertainties.
>> >
>> > The change is to the datum. How this will work out with future global
>> > datums we will have to wait and see.
>> >
>> > In another 30 years there will probably be another change of around 1.5
>> > metres again.
>>
>> As receivers become more accurate and folks start use other ground based
>> positioning technology that gives millimetre accuracy, then that data in
>> OSM will over time become more out of sync as the tectonic plate moves
>> while the coordinate system remains fixed.
>>
>> When that happens it would be good to see a future OSM API that lets us
>> upload data in a coordinate system like GDA so that we don't need to be
>> constantly updating coordinates to reflect the move in the techtonic
>> plate.
>>
>>
>>
>> ------------------------------
>>
>> Message: 4
>> Date: Sat, 30 Jul 2016 16:22:42 +1000
>> From: Warin <61sundowner at gmail.com>
>> To: talk-au at openstreetmap.org
>> Subject: Re: [talk-au] Australia "changing coordinates"
>> Message-ID: <5d2da84e-151b-b07c-4e33-57fc7a068eaf at gmail.com>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>>
>> On 7/30/2016 1:57 PM, Andrew Harvey wrote:
>> > On Sat, 30 Jul 2016, at 08:40 AM, Warin wrote:
>> >> The change, distance wise, is upto 1.5 metres, well within commercial
>> >> GPS uncertainties.
>> >>
>> >> The change is to the datum. How this will work out with future global
>> >> datums we will have to wait and see.
>> >>
>> >> In another 30 years there will probably be another change of around
1.5
>> >> metres again.
>> > As receivers become more accurate and folks start use other ground
based
>> > positioning technology that gives millimetre accuracy, then that data
in
>> > OSM will over time become more out of sync as the tectonic plate moves
>> > while the coordinate system remains fixed.
>> >
>> > When that happens it would be good to see a future OSM API that lets us
>> > upload data in a coordinate system like GDA so that we don't need to be
>> > constantly updating coordinates to reflect the move in the techtonic
>> > plate.
>>
>> Sigh.
>>
>> Simply changing from AGD66 to GDA94 can produce a change of around 100
metres in location of a coordinate.
>> So a change in datum can correct the drift without changing the
coordinates.
>>
>>
>>  From the above you can see that OZ moves at upto about 50 mm per year.
>>
>> At present there is no datum system that 'drifts' over time, that would
give a system that would need little alteration and fewer of them.
>>
>> People who require the accuracy take into account the drift (usually
professional surveyors with very expensive receivers, antennas etc.).
>>
>>
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Subject: Digest Footer
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>> ------------------------------
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>> End of Talk-au Digest, Vol 109, Issue 22
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