<div dir="ltr"><p style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Hello all,</span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap"><br>

</span></p><p style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">This query is about a discrepancy between projection results using the <b>Custom CRS Test</b> and <b>on-the-fly</b> transformation, and not about RSO per se.</span></p>

<p style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap"><br>

</span></p><p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">The Proj4 parameters for GDM2000 / Peninsula RSO (EPSG:3375) as given by epsg_tr.py (GDAL 1.9.2) are:</span></p>

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<span style="font-size:15px;background-color:transparent;vertical-align:baseline;white-space:pre-wrap"><font face="courier new, monospace">+proj=omerc +lat_0=4 +lonc=102.25 +alpha=323.0257964666666 +k=0.99984 +x_0=804671 +y_0=0 +gamma=323.1301023611111 +ellps=GRS80 +units=m +no_defs</font></span></p>

<br style="font-family:arial,sans-serif;font-size:13px"><span style="background-color:transparent;font-size:15px;font-family:Arial;vertical-align:baseline;white-space:pre-wrap"></span><p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt">

<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">This Malaysian projection requires the </span><span style="font-size:15px;font-family:Arial;background-color:transparent;font-weight:bold;vertical-align:baseline;white-space:pre-wrap">+no_off</span><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap"> or <b>+no_uoff</b> flag (both works) for rotation at the natural origin as of proj 4.8. </span><span style="background-color:transparent;font-family:Arial;font-size:15px;white-space:pre-wrap;line-height:1.15">To test, I created a custom CRS based on GDM2000 / Peninsula RSO adding this flag. However, there seems to be some discrepancy between the on-the-fly derived results and the Test in the Custom CRS definition dialog.</span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="background-color:transparent;font-family:Arial;font-size:15px;white-space:pre-wrap;line-height:1.15"><br>

</span></p><p style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="background-color:transparent;font-family:Arial;font-size:15px;white-space:pre-wrap;line-height:1.15">I set the project CRS as the custom CRS I created and added the test point in WGS84.</span></p>

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<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Test points: <b>1.827764875</b> deg N, <b>103.640259872222</b> deg E (WGS84 EPSG:4326)</span></p><p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt">

<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">Expected results: Northing <b>202,122.062</b> m, Easting <b>627,096.132</b> m (EPSG:3375)</span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">
</span></p><p style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap"><i>The test points and projected coordinates are taken from the GDM2000 Technical Manual published by the Department of Survey and Mapping Malaysia.</i></span></p>

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<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap"><u>Test results (standard EPSG:3375)</u>:  </span></p><p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt">

<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">cs2cs — -240332.04, 958936.71</span></p><p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt">

<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">QGIS Master (13d35ac) On-the-fly derived: Y = -240,332.0326, X = 958,936.7057</span></p><p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt">

<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">QGIS Master (13d35ac) Custom CRS Test:<b> -240,332.0326</b> N, <b>958,936.7057</b> E</span></p><p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt">

<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">QGIS 1.8 On-the-fly: projected coordinates not derived</span></p><p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt">

<span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">QGIS 1.8 Custom CRS Test: -240,332.0326 N, 958,936.7057 E</span></p><br style="font-family:arial,sans-serif;font-size:13px">

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap"><u>Test results (with <b>+no_off</b> flag)</u>:  </span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">cs2cs — 202122.06,  627096.13</span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">QGIS Master (13d35ac) On-the-fly derived: Y =<b> -240,332.0326</b>, X = <b>958,936.7057</b></span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">QGIS Master (13d35ac) Custom CRS Test: <b>202,122.0625</b> N, <b>627,096.1317</b> E</span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">QGIS 1.8 On-the-fly: projected coordinates not derived</span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">QGIS 1.8 Custom CRS Test: 202,122.0625 N, 627,096.1317 E</span></p>

<p dir="ltr" style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap"><br>

</span></p><p style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><span style="font-size:15px;font-family:Arial;background-color:transparent;vertical-align:baseline;white-space:pre-wrap">It looks like the Custom CRS Definition Test dialog is giving the correct result, but the on-the-fly transformation is ignoring the +no_off flag.</span></p>

<p style="font-size:medium;font-family:'Times New Roman';line-height:1.15;margin-top:0pt;margin-bottom:0pt"><br></p><p style="font-family:arial,sans-serif;font-size:13px;margin-top:0pt;margin-bottom:0pt"><font face="Arial"><span style="font-size:15px;line-height:17px;white-space:pre-wrap">Is the on-the-fly transformation using a different transformation process and reading the proj4 parameters differently, or am I going about this wrongly?</span></font></p>

<p style="font-family:arial,sans-serif;font-size:13px;margin-top:0pt;margin-bottom:0pt"><font face="Arial"><span style="font-size:15px;line-height:17px;white-space:pre-wrap"><br></span></font></p><p style="font-family:arial,sans-serif;font-size:13px;margin-top:0pt;margin-bottom:0pt">

<font face="Arial"><span style="font-size:15px;line-height:17px;white-space:pre-wrap">Regards</span></font></p></div>