<HTML dir=ltr><HEAD><TITLE>[Gvsig_english] BIG problems with reprojecting AGD66 to GDA94</TITLE>
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<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Hello, Simon.</FONT></DIV>
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<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">I have done a test with a view in EPSG:4202 and two shapefiles (a target shapefile in EPSG:4202 and a source shapefile in </FONT><FONT color=#000000 size=3 face="Times New Roman">EPSG:4283) extracted from your DBF. </FONT><FONT color=#000000 size=3 face="Times New Roman">After adding the target shapefile (same projection as the view) I have added the source shp trying a variety of transformations. </FONT><FONT color=#000000 size=3 face="Times New Roman">When you add it to the view, gvSIG lets you choose among eleven available "EPSG transformations" between those two EPSG </FONT><FONT color=#000000 size=3 face="Times New Roman">codes. The one that gives me the best result is the first one:</FONT></DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Transformation code: 1278</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Name: AGD66 to GDA94 (1)</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">(we are actually doing the inverse transformation (GDA94 to AGD66) but the algorithm seems to be aware of this and does it well)</FONT></DIV>
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<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">I have measured the distance between the obtained coordinates (transformed source shp) and the expected coordinates (target shp) </FONT><FONT color=#000000 size=3 face="Times New Roman"> for 5 random points and I get these errors:</FONT></DIV>
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<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">1.2 m</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">0.9 m</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">1.57 m</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">0.88 m</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">0.96 m</FONT></DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">I have also looked into some pdf files and I have found these parameters (AGD66 to GDA94) for Victoria and NSW:</FONT></DIV>
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<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman"><A href="http://www.icsm.gov.au/icsm/gda/gdatm/gdav2.3.pdf">http://www.icsm.gov.au/icsm/gda/gdatm/gdav2.3.pdf</A></FONT></DIV>
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<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Dx = -119.353</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Dy = -48.301</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Dz = 139.484</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Rx = -0.415</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Ry = -0.26</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Rx = -0.437</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Sc = -0.613</FONT></DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Since we are doing the inverse transfomation, we should reverse the sign for each parameter, but I don't get good results.</FONT></DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">I have also read somewhere that in Australia and the US, the rotation parameters have the inverse meaning than in Europe (big ???), so I tried these parameters (reversing the ones above except for the rotation parameters):</FONT></DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Dx = 119.353</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Dy = 48.301</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Dz = -139.484</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Rx = -0.415</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Ry = -0.26</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Rx = -0.437</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Sc = 0.613</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman"></FONT> </DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">And indeed, I get significantly smaller errors for those 5 points:</FONT></DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">0.7 m</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">0.15 m</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">0.75 m</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">0.8 m</FONT></DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">0.25 m</FONT></DIV>
<DIV dir=ltr> </DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman">Those 7 parameters can be entered with the "manual transformation" option. </FONT><FONT color=#000000 size=3 face="Times New Roman">I didn't get the grid to work either, sorry, although the format seems to be one supported by gvSIG. And I have not done any tests with non-geographical SRS.</FONT></DIV></DIV>
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<DIV dir=ltr>Regards,</DIV>
<DIV dir=ltr><FONT color=#000000 size=3 face="Times New Roman"></FONT> </DIV></DIV>
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<DIV><FONT size=2 face="Courier New"><FONT size=3 face="Times New Roman">Juan Lucas Domínguez Rubio<BR></FONT>---</FONT></DIV>
<DIV><FONT size=2 face="Courier New"><FONT size=2 face="Courier New"><FONT size=2 face="Courier New">Prodevelop SL, Valencia (España)</FONT></DIV>
<DIV>
<DIV><FONT size=2 face="Courier New">Tlf.: 96.351.06.12 -- Fax: 96.351.09.68<BR></FONT><A href="http://www.prodevelop.es/"><FONT size=2 face="Courier New">http://www.prodevelop.es</FONT></A><BR><FONT size=2 face="Courier New">---</FONT></DIV></FONT></DIV></FONT></DIV>
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<FONT size=2 face=Tahoma><B>De:</B> gvsig_internacional-bounces@listserv.gva.es en nombre de Simon Cropper (Botanicus Australia Pty Ltd)<BR><B>Enviado el:</B> sáb 28/11/2009 7:36<BR><B>Para:</B> Users and Developers mailing list<BR><B>Asunto:</B> [Gvsig_english] BIG problems with reprojecting AGD66 to GDA94<BR></FONT><BR></DIV>
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<P><FONT size=2>Hi Guys,<BR><BR>I am having problems getting the reproject tool to work as expected with<BR>Australian Projections/Datums.<BR><BR>If I create a shapefile in AGD66 then reproject the file to GDA94 using<BR>the reproject tool, the points are moved but only ~20m rather than 204<BR>metres northeast of the original position. If I use the resulting GDA94<BR>file in the AGD66 View and tell the program, it reprojects on the fly<BR>and the points overlap.<BR><BR>This shows (a) that the reproject on the fly facility works, and (b) I<BR>appear to have chosen the wrong projection.<BR><BR>The problem is I have tried reprojecting northing-eastings,<BR>latitude-longitude, in EPSG and ESRI format but can't get the correct<BR>reprojection. I have been using EPSG:4202 for AGD66 geographicals,<BR>EPSG:4283 for GDA94 geographicals, EPSG:20255 for AGD/ AMG zone 55 and<BR>EPSG:28355 for GDA94/MGA zone 55. I have also tried ESRI: 28355 and<BR>ESRI:20255 with no luck.<BR><BR>I have even downloaded the transformation grid but not been able to get<BR>this to work either.<BR><BR>Can anyone help?<BR><BR>Attached is a list of points in a table that are released by the local<BR>government apparently created by FME. This has the comparable<BR>coordinates in 4 commonly used projections for 160 distinct points<BR>across Victoria.<BR><BR>Can anyone get the correct setting and procedure to get these points to<BR>superimpose when reprojecting on the fly and for the reproject facility<BR>to work correctly?<BR><BR>I have also included some useful links to help the more industrious and<BR>knowledgeable to figure out what is wrong.<BR><BR><A href="http://www.land.vic.gov.au/Land/lcnlc2.nsf/LinkView/9B33746B3D77040F4A256A250008E70A5B923E73477D6D65CA256E5F0013D73B">http://www.land.vic.gov.au/Land/lcnlc2.nsf/LinkView/9B33746B3D77040F4A256A250008E70A5B923E73477D6D65CA256E5F0013D73B</A><BR><BR><A href="http://www.icsm.gov.au/icsm/gda/gdatm/">http://www.icsm.gov.au/icsm/gda/gdatm/</A><BR><BR><A href="http://www.icsm.gov.au/icsm/gda/gdatm/gdav2.3.pdf">http://www.icsm.gov.au/icsm/gda/gdatm/gdav2.3.pdf</A><BR><BR>Any help would be appreciated as I am trying to tick this off my list of<BR>things gvSIG can do, and was surprised to see when resulting reprojected<BR>files were compared to external reference documents they did not align.<BR><BR>Any help would be greatly appreciated.<BR>--<BR><BR>Cheers Simon<BR><BR>Simon Cropper<BR>Botanicus Australia Pty Ltd<BR>PO Box 160, Sunshine, Victoria 3020.<BR>P: 9311 5822. M: 041 830 3437.<BR>mailto: scropper@botanicusaustralia.com.au<BR><<A href="mailto:scropper@botanicusaustralia.com.au">mailto:scropper@botanicusaustralia.com.au</A>><BR>web: www.botanicusaustralia.com.au <<A href="http://www.botanicusaustralia.com.au/">http://www.botanicusaustralia.com.au</A>><BR><BR></FONT></P></DIV></BODY></HTML>