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<font size="+1"><small>Brett / All,<br>
<br>
I had a go at changing the AGD66 and AGD84 definitions in the QGIS
database (srs.db) to include the towgs84 parameters and it appears to
have worked. The attached image shows the same point assigned to GDA94,
AGD66 and AGD84 with the offsets as expected. The
updated srs.db can be found at <a class="moz-txt-link-freetext"
href="http://dl.dropbox.com/u/9546967/srs.db">http://dl.dropbox.com/u/9546967/srs.db</a>
if you would like to use it.<br>
<br>
The new srs.db was generated by running the following queries on srs.db
in SQLite Database Browser<br>
<br>
UPDATE tbl_srs set parameters=replace(parameters, '+ellps=aust_SA',
'+a=6378160 +rf=298.250000000055
+towgs84=-117.763,-51.51,139.061,-0.292,-0.443,-0.277,-0.191') where
description like 'AGD84%'<br>
<br>
</small></font><font size="+1"><small>UPDATE tbl_srs set
parameters=replace(parameters, '+ellps=aust_SA', '+a=6378160
+rf=298.250000000055
+towgs84=-129.193,-41.212,130.73,-0.246,-0.374,-0.329,-2.955') where
description like 'AGD66%'<br>
<br>
Not sure how this compares to Ken and Giovanni's method.<br>
<br>
Cheers,<br>
<br>
Roland<br>
<br>
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<div class="moz-signature">-- <br>
<strong><font face="Arial" color="#000080">ROLAND HILL</font></strong><br>
<strong><font face="Arial" color="#000080" size="2">Director</font></strong><br>
<strong><font face="Arial" color="#000080" size="2">Four Winds
Technology Pty Ltd</font></strong><br>
<strong><font face="Arial" color="#000080" size="2">Ph/Fax : +61
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+61 (0)41 880 7472</font></strong><br>
<strong><font face="Arial" color="#000080" size="2"><a
href="mailto:Roland.Hill@fourwindstechnology.com.au">Roland.Hill@fourwindstechnology.com.au</a></font></strong>
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On 23/09/10 15:47, Brett Adams wrote:
<blockquote cite="mid:4C9AE9FF.9040101@gmail.com" type="cite"> Ken, <br>
That's a legendary effort if your getting sensible results with the
icsm files. Do you think the format is suitable that it could be used
in a sponsored bug fix? <br>
<br>
I gave this a shot myself but couldn't get it run at all, but then I
have no idea what I'm doing so thats no real indication. <br>
<br>
I've had no success in getting parameters to stick (AGD66, AGD84 or
GDA94) on shape or mapinfo files. <br>
<br>
Following solution was proposed by Roland Hill (22/09/2010 8:59pm) <br>
<br>
If your Custom CRS database does not appear to be working properly (ie
you can see your custom CRS, but it isn't sticking to your data
properly), then try to find your custom CRS database (qgis.db in your
home directory on Linux, I guess it is in Application Settings or
something similar in Windows) and delete it in case you have an old one
with an incorrect format. <br>
<br>
<br>
Brett <br>
<br>
On 23/09/2010 12:47 PM, Ken Norris wrote: <br>
<blockquote type="cite">As Micha suggested, the National AGD66
distortion grid at <br>
<a class="moz-txt-link-freetext"
href="http://www.icsm.gov.au/icsm/gda/gdatm/national66.zip">http://www.icsm.gov.au/icsm/gda/gdatm/national66.zip</a>
<br>
and AGD84 distortion grid at <br>
<a class="moz-txt-link-freetext"
href="http://www.icsm.gov.au/icsm/gda/gdatm/national84.zip">http://www.icsm.gov.au/icsm/gda/gdatm/national84.zip</a>
<br>
seem to be the way forward. <br>
<br>
When unzipped, put into the proj directory (for me usr/share/proj) and <br>
coupled via the +nadgrids= parameter in a Custom CRS, it seems to yield
the <br>
correct transform when tested. <br>
<br>
+proj=utm +zone=55 +south +ellps=aust_SA +nadgrids=AGD66.gsb +units=m <br>
+no_defs <br>
<br>
(I renamed the unzipped distortion file 'A66 National (13.09.01).gsb'
file <br>
to 'AGD66.gsb' for convenience) <br>
<br>
But I can't make the parameters stick in the CRS of a vector file using
the <br>
override facility. Any ideas? <br>
<br>
<br>
</blockquote>
<br>
<br>
</blockquote>
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