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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi Even, Hi Thomas,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks for your response and sorry for the late reply. School holidays and sickness generated quite some delays across my team.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Anyway, meanwhile we have improved our methodology for measuring the performance, by using JMH (<span lang=DE><a href="https://openjdk.java.net/projects/code-tools/jmh/"><span lang=EN-US>https://openjdk.java.net/projects/code-tools/jmh/</span></a></span>). What we found is that coordinate transformations have change their performance by roughly these margins:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>GDAL 2.3.3 over GDAL 2.3.1, both with PROJ 4.8.0 (without ETMERC): <o:p></o:p></p><p class=MsoNormal>+50% WGS84 -> UTM projection and vice versa<o:p></o:p></p><p class=MsoNormal>+30% between different UTM projections<o:p></o:p></p><p class=MsoNormal>-10% UTM projection -> DHDN projection<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>GDAL 2.3.3 with PROJ 5.2.0 over GDAL 2.3.3 with PROJ 4.8.0 (with ETMERC):<o:p></o:p></p><p class=MsoNormal>+48% WGS84 -> UTM projection<o:p></o:p></p><p class=MsoNormal>+23% UTM projection -> WGS84<o:p></o:p></p><p class=MsoNormal>+60% between different UTM projections<o:p></o:p></p><p class=MsoNormal>+23% UTM projection -> DHDN projection<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>GDAL 2.4 adds another small margin across the board.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Overall, some of the transformations have indeed doubled their computation time.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hope this is useful. If anyone is interested in the test sources, do let me know.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards,<o:p></o:p></p><p class=MsoNormal>Stefan<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b>From:</b> Thomas Knudsen <knudsen.thomas@gmail.com> <br><b>Sent:</b> Tuesday, January 29, 2019 12:13<br><b>To:</b> Even Rouault <even.rouault@spatialys.com><br><b>Cc:</b> Stefan Moebius <Stefan.Moebius@amdocs.com>; gdal-dev@lists.osgeo.org<br><b>Subject:</b> Re: [gdal-dev] Perforce issue in coordinate transformations with Gdal 2.3.2<o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><div><p class=MsoNormal>Prepare/finalize functions were added to pj_inv & pj_fwd in PROJ PR #731 (<a href="https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FOSGeo%2Fproj.4%2Fpull%2F731&data=02%7C01%7CStefan.Moebius%40amdocs.com%7C1af750be00dc439e8af008d685dade61%7Cc8eca3ca127646d59d9da0f2a028920f%7C0%7C0%7C636843572476979244&sdata=SFr4nL70uT6NxoNcMnIYuxCxfhVmt4airGGxvPAhY9g%3D&reserved=0">https://github.com/OSGeo/proj.4/pull/731</a>), in order to resolve ticket #700 (<a href="https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FOSGeo%2Fproj.4%2Fissues%2F700&data=02%7C01%7CStefan.Moebius%40amdocs.com%7C1af750be00dc439e8af008d685dade61%7Cc8eca3ca127646d59d9da0f2a028920f%7C0%7C0%7C636843572476979244&sdata=Wl1zUW%2BpkP%2Bu6phlj7OY%2B9oJtmMYUTM4Xa5pazHvB1E%3D&reserved=0">https://github.com/OSGeo/proj.4/issues/700</a>).<o:p></o:p></p></div><div><p class=MsoNormal>These add some overhead as well but IIRC, more like +15% (much depending on the actual projection) than +100%. <o:p></o:p></p></div></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>Den man. 28. jan. 2019 kl. 17.38 skrev Even Rouault <<a href="mailto:even.rouault@gmail.com">even.rouault@gmail.com</a>>:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt'><div><div><div><div><p class=MsoNormal>Stefan,<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I bet you also upgraded your PROJ version in the process ? I can't think of a reason in GDAL itself for a performance change. But on the PROJ side, yes, there might be some explanation<o:p></o:p></p></div><div><p class=MsoNormal>The main one I can see is that in PROJ 4.9.3, the Extended Transverse Mercator is used by default for UTM, which has probably a higher computation time. If you define the GDAL configuration option / environmenet variable OSR_USE_ETMERC to NO, then the older Transverse Mercator method will be used.<o:p></o:p></p></div><div><p class=MsoNormal>PROJ 5.0 has also undergone major changes that might have increased a bit the computation time, but I wouldn't expect them to cause a 2x slowdown.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Even<o:p></o:p></p></div><div><p class=MsoNormal><br>-- <br>Spatialys - Geospatial professional services<br><a href="https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.spatialys.com&data=02%7C01%7CStefan.Moebius%40amdocs.com%7C1af750be00dc439e8af008d685dade61%7Cc8eca3ca127646d59d9da0f2a028920f%7C0%7C0%7C636843572476979244&sdata=a6NUnvhbQs8olqMY9%2B6zEr959T4KT1Iq2q0z9lUX18w%3D&reserved=0" target="_blank">http://www.spatialys.com</a><o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p></div></div></div><p class=MsoNormal>_______________________________________________<br>gdal-dev mailing list<br><a href="mailto:gdal-dev@lists.osgeo.org" target="_blank">gdal-dev@lists.osgeo.org</a><br><a href="https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.osgeo.org%2Fmailman%2Flistinfo%2Fgdal-dev&data=02%7C01%7CStefan.Moebius%40amdocs.com%7C1af750be00dc439e8af008d685dade61%7Cc8eca3ca127646d59d9da0f2a028920f%7C0%7C0%7C636843572476979244&sdata=UjdRV5U5KE7Ao9%2Bfx0KlpzZIgzTN%2FCIoCg8tWRtjXNg%3D&reserved=0" target="_blank">https://lists.osgeo.org/mailman/listinfo/gdal-dev</a><o:p></o:p></p></blockquote></div></div></div></body></html>