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--></style></head><body bgcolor="white" lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thanks Zoltan,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I understand the process a little better now. Will have a look tonight and see if I can get the points into the correct location.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Many thanks for your help,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Wesley</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><div><div style="border:none;border-bottom:solid windowtext 1.5pt;padding:0in 0in 1.0pt 0in"><p class="MsoNormal" style="border:none;padding:0in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><img width="334" height="103" id="_x0000_i1027" src="cid:image001.jpg@01CFDBFC.B906DCF0" alt="Email_Signature"></span></p></div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Wesley Roberts, PhD</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Geospatial Manager</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Biocarbon Partners</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><a href="mailto:wesley@biocarbonpartners.com"><span style="color:#0563c1">wesley@biocarbonpartners.com</span></a></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Cell RSA: +27 83 5355 646</span></p></div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><div><div style="border:none;border-top:solid #e1e1e1 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext"> <a href="mailto:africa-bounces@lists.osgeo.org">africa-bounces@lists.osgeo.org</a> [mailto:<a href="mailto:africa-bounces@lists.osgeo.org">africa-bounces@lists.osgeo.org</a>] <b>On Behalf Of </b>Zoltan Szecsei<br><b>Sent:</b> Monday, September 29, 2014 3:33 PM<br><b>To:</b> <a href="mailto:africa@lists.osgeo.org">africa@lists.osgeo.org</a><br><b>Subject:</b> Re: [OSGeo Africa] Surveyor General Diagram - Mapping property boundary points</span></p></div></div><p class="MsoNormal"> </p><div><p class="MsoNormal">Hi All,<br>The "missing step" is the Datum shift.<br>If you do it manually, then the sequence is "Cape Lo19 to LatLong <=Datum shift=>LatLong to Harte94 WG19"<br>If with QGIS you specify your original CRS n Cape Lo19 and your Tagert CRS on Harte94 WG19 the QGIS should handle the Datum shift, and it will seem transparent to you.<br><br>The "Survey Convention" is South Africa is to use the "Lo" prefix to suggest Cape Datum, and the "WG" prefix to show WGS84, Harte94 Datum. The numeric value after the "Lo" and the "WG" is the longitude of the central meridian.<br><br>HTH,<br>Zoltan<br><br><br>On 2014/09/29 15:20, Dr Wesley Roberts wrote:</p></div><blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hi Sarel,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Many thanks for the input. I have found the specific EPSG and as before the same location appears to have different coordinates to those specified on the surveyors diagram. I think I am missing a step here. Based on Zoltans response I think I need an intermediate step to get the points into the correct location, is this correct?</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">So, my workflow is </span></p><p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">1.</span><span style="font-size:7.0pt;color:#1f497d"> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Generate text file with X and Y coordinates</span></p><p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">2.</span><span style="font-size:7.0pt;color:#1f497d"> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Open in QGIS using delimited text file import </span></p><p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">3.</span><span style="font-size:7.0pt;color:#1f497d"> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Assign a suitable projection to the mapped points (LO19 Cape Datum)</span></p><p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">………An intermediate step……… <- Think of the maths cartoon where the prof says “and then a miracle happens”</span></p><p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">4.</span><span style="font-size:7.0pt;color:#1f497d"> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Re-project to WGS 84\</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I am still lost when it comes to the north facing vs south facing projection and how I get the proj to match the coordinates on the SG diagram. Could this not al be a change in the constant?</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Regards,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Wesley</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><div style="border:none;border-bottom:solid windowtext 1.5pt;padding:0in 0in 1.0pt 0in"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><img border="0" width="334" height="103" id="Picture_x0020_1" src="cid:image001.jpg@01CFDBFC.B906DCF0" alt="Email_Signature"></span></p></div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Wesley Roberts, PhD</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Geospatial Manager</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Biocarbon Partners</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><a href="mailto:wesley@biocarbonpartners.com"><span style="color:#0563c1">wesley@biocarbonpartners.com</span></a></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Cell RSA: +27 83 5355 646</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <a href="mailto:africa-bounces@lists.osgeo.org">africa-bounces@lists.osgeo.org</a> [mailto:<a href="mailto:africa-bounces@lists.osgeo.org">africa-bounces@lists.osgeo.org</a>] <b>On Behalf Of </b>S Coetzer<br><b>Sent:</b> Monday, September 29, 2014 3:05 PM<br><b>To:</b> Africa local chapter discussions<br><b>Subject:</b> Re: [OSGeo Africa] Surveyor General Diagram - Mapping property boundary points</span></p><p class="MsoNormal"> </p><div><div><div><div><p class="MsoNormal" style="margin-bottom:12.0pt">Hi Wesly</p></div><p class="MsoNormal" style="margin-bottom:12.0pt">Zoltan is correct, use Cape datum for 1975 data, I think the EPSG code is: 22279</p></div><p class="MsoNormal" style="margin-bottom:12.0pt">In QGIS, use 22279 to filter your CRS and you'lle find it.</p></div><p class="MsoNormal">Good luck.</p></div><div><p class="MsoNormal"><br clear="all"></p><div><p class="MsoNormal">Sarel Coetzer </p></div><p class="MsoNormal"> </p><div><p class="MsoNormal">On Mon, Sep 29, 2014 at 2:37 PM, Dr Wesley Roberts <<a href="mailto:wesley@biocarbonpartners.com" target="_blank">wesley@biocarbonpartners.com</a>> wrote:</p><blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt"><div><div><p class="MsoNormal">Dear Colleagues,</p><p class="MsoNormal"> </p><p class="MsoNormal">A friend has asked me to produce a map using a title deed SG document. The property in question was surveyed in 1975 and it appears to make use of the LO19 coordinate system. I am not that familiar with LO19 and am having some trouble with defining a proj 4 projection in QGIS. I have produced a custom CRS based on the this post by Gavin Flemming (<a href="http://afrispatial.co.za/foss-gis/south-african-projections-in-foss-gis/" target="_blank">http://afrispatial.co.za/foss-gis/south-african-projections-in-foss-gis/</a>). All seems well until I look at the location, I can find it using ancillary data. The coordinates on the title deed match only in the X domain (I have swopped both the X and the Y as well as the sign) while the Y domain appears to be “way out”. The SG title deed coordinate for one of the Y points is -9105.30 (Constant +9 760 000,00) while the same location in the QGIS returns a Y coordinate of around -3 769 758. Can anyone shed light on why there is such a large difference between the SG Diagram and the actual location?</p><p class="MsoNormal"> </p><p>1.<span style="font-size:7.0pt"> </span>I am thinking that it might be something to do with the fact that the property was surveyed in 1975, any ideas?</p><p>2.<span style="font-size:7.0pt"> </span>I have used the following proj 4 definition – have I missed something?</p><p> </p><p class="MsoNormal">+proj=tmerc +lat_0=0 +lon_0=19 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs</p><p class="MsoNormal"> </p><p class="MsoNormal">Any help on this matter would be greatly appreciated.</p><p class="MsoNormal"> </p><p class="MsoNormal">Regards,</p><p class="MsoNormal">Wesley</p><p class="MsoNormal"> </p><div style="border:none;border-bottom:solid windowtext 1.5pt;padding:0in 0in 1.0pt 0in"><p class="MsoNormal"><img border="0" width="334" height="103" id="_x0000_i1026" src="cid:image001.jpg@01CFDBFC.B906DCF0" alt="Email_Signature"></p></div><p class="MsoNormal">Wesley Roberts, PhD</p><p class="MsoNormal">Geospatial Manager</p><p class="MsoNormal">Biocarbon Partners</p><p class="MsoNormal"><a href="mailto:wesley@biocarbonpartners.com" target="_blank">wesley@biocarbonpartners.com</a></p><p class="MsoNormal">Cell RSA: +27 83 5355 646</p><p class="MsoNormal"> </p></div></div><p class="MsoNormal"><br>_______________________________________________<br>Africa mailing list<br><a href="mailto:Africa@lists.osgeo.org">Africa@lists.osgeo.org</a><br>You can UNSUBSCRIBE at <a href="http://lists.osgeo.org/mailman/listinfo/africa" target="_blank">http://lists.osgeo.org/mailman/listinfo/africa</a></p></blockquote></div><p class="MsoNormal"> </p></div><p class="MsoNormal"><br><br><br></p><pre>_______________________________________________</pre><pre>Africa mailing list</pre><pre><a href="mailto:Africa@lists.osgeo.org">Africa@lists.osgeo.org</a></pre><pre>You can UNSUBSCRIBE at <a href="http://lists.osgeo.org/mailman/listinfo/africa">http://lists.osgeo.org/mailman/listinfo/africa</a></pre></blockquote><p class="MsoNormal"><br><br><br></p><pre>-- </pre><pre> </pre><pre>===========================================</pre><pre>Zoltan Szecsei PrGISc [PGP0031]</pre><pre>Geograph (Pty) Ltd.</pre><pre>GIS and Photogrammetric Services</pre><pre> </pre><pre>P.O. Box 7, Muizenberg 7950, South Africa.</pre><pre> </pre><pre>Mobile: +27-83-6004028</pre><pre>Fax: +27-86-6115323 <a href="http://www.geograph.co.za">www.geograph.co.za</a></pre><pre>===========================================</pre></div></body></html>