[talk-au] New CC-BY datasets due Monday 28 September on Government 2.0 Taskforce website

[Dan O'Hara]

Here is some info on the ACT grid"The ACT grid is a Transverse Mercator map projection that uses the
longitude of Mt Stromlo Trig Station as its central meridian.  It is
based on the Australian Geodetic Datum 66 (AGD66), which is modified to
take advantage of the ACT’s limited east-west dimension and account for
scale differences caused by the ACT’s height above sea level.  The
resulting ACT grid effectively can be treated as a plane (rather than
geodetic) system of coordinates using the formulae of plane
trigonometry, without the need to apply scale factors, grid
convergence, arc-to-chord, or sea level corrections. As a result, for
all but the most accurate work in the ACT, terrestrial, grid and plane
measurements can be taken as being identical."

http://www.actpla.act.gov..au/tools_resources/maps_land_survey/surveying_data/surveyors_information/coordinate_system

I think the reason you didn't get a match is because the grid reference is in yards not metres.




________________________________
From: Alex (Maxious) Sadleir <maxious at gmail.com>
To: OSM Australian Talk List <talk-au at openstreetmap.org>
Sent: Wednesday, 30 September, 2009 9:27:36 PM
Subject: Re: [talk-au] New CC-BY datasets due Monday 28 September on Government 2.0 Taskforce website

On Wed, Sep 30, 2009 at 9:13 PM, terryc <terryc at woa.com.au> wrote:
> Alex (Maxious) Sadleir wrote:
>
>> For example, Telopea Park has these two that I think I can remember:
>> Toilet Block: X=211,550,Y=600,191 (-35.31415853430738,149.13748919963837)
> AMG (lat/lon?)
>
>> BBQ: X=211,576, Y=600,137 (-35.314867659800925,149.13786470890045)

Sorry, the very accurate ones were me giving a estimate of where I
think the X/Y points should be if anybody wanted to try a few
different systems and see if any matched. I did think it looked
similar to UTM but the locations don't seem to match when I try them
on the Geoscience site @
http://www.ga.gov.au/geodesy/datums/redfearn_geo_to_grid.jsp
The commas are probably a red herring, in other parts of the files
years are written as 2,007.

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