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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hi,<o:p></o:p></p><p class=MsoNormal>I’m trying to write C++ code referencing the proj7 API, to convert a set of lat/lon/alt points to a user-specified target CRS. Following the example in the proj documentation, I use proj_create_crs_to_crs() to establish source and target CRS, then proj_trans() to transform individual points. I hopes of validating the results, I thought I should test by feeding the same input coordinates to cs2cs on the command line, with the same CRS definitions (using epsg:xxxx+yyyy form in both the code and the cs2cs command), but I get different results, not outrageous but as much as dozens of meters. In some simpler tests, using only epsg:xxxx, I can get matching results. Is there something special about the epsg:xxxx+yyyy format that needs to be treated differently in C++ code vs. the command line usage?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>For example:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>echo "-33 151 5" | cs2cs -d 8 EPSG:4326+5773 +to EPSG:7856+5711<o:p></o:p></p><p class=MsoNormal>313152.77721557 6346936.49571435 5.28067830<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>But with the same input values in the C++ code, the results are<o:p></o:p></p><p class=MsoNormal>313188.89746084268 6347047.2885914352 4.940935415625713<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Am I missing something fundamental here?<o:p></o:p></p><p class=MsoNormal>Thanks!<o:p></o:p></p></div><div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br />
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