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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Hello,<o:p></o:p></p><p class=MsoNormal>I have a set of ground control points provided by a surveyor in Australia that were created in June 2020.<o:p></o:p></p><p class=MsoNormal>They are expressed in MGA94 / Zone 56 CRS, which I believe is EPSG:28356.<o:p></o:p></p><p class=MsoNormal>I would like to convert these points to MGA2020 (EPSG:7856) and relate them to actual data coming from a Trimble GPS today.<o:p></o:p></p><p class=MsoNormal>Using PROJ7, I am able to get transformed values between MGA94 and MGA2020 that reflect the displacement of the Australian continent between those CRSs, e.g. (using some round numbers to illustrate here)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>echo 300000 6000000 0 | cs2cs +init=epsg:28356 +to +init=epsg:7856 -d 3<o:p></o:p></p><p class=MsoNormal>300000.435 6000001.421 0.000<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>However, in comparing the results to current readings from the GPS, I see they’re off by what may be the continental drift that’s occurred in the last 15 months – about 8 cm northeast.<o:p></o:p></p><p class=MsoNormal>I know PROJ7 knows about time-dependent transformations, I just can’t seem to figure out how to use that to get my GCP coordinates in today’s MGA2020 grid. I’ve naively tried<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>echo 300000 6000000 0 2020.5 | cs2cs +init=epsg:28356 +to +init=epsg:7856 -d 3<o:p></o:p></p><p class=MsoNormal>300000.435 6000001.421 0.000 2020.5<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>but it comes up with the same numbers. <o:p></o:p></p><p class=MsoNormal>Do I need to construct a more elaborate pipeline, and is this even something cs2cs can be used for?<br>Any tips or tricks would be appreciated! As you might have guessed, I’m pretty much a novice with PROJ7.<o:p></o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal>Henning Pangels<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div><div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br />
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