Canadian NAD83 (CSRS) definition issue

[Phogi]

Hi Alexey,

When I looked at the projection in Agisoft e.g. EPSG:3780 based on NAD83(CSRS), it has the part of "TOWGS84[-0.991,1.9072,0.5129,0.025789907519493,0.009650098960270401,0.011659943232342,0]", while in https://epsg.io/3780 it shows "TOWGS84[0,0,0,0,0,0,0]".

This caused the conversion difference between using Agisoft and other software. Can you tell me which one should be the correct one? Where does the values in Agisoft's definition for towgs84 come from?

Thanks a lot!

Phogi

[Phogi]

Hi Alexey,

I found the definition will have some difference in Agisoft's toWGS84 parameters can explain NAD83 (CSRS)'s difference, but I met another coodinate at South Africa, e.g. EPSG:2046. In Agisoft, the WGS84 lat/lon (-27.77286878,28.45085189) will be (-1332755.012, 3147049.104), while in epsg.io it will be (-1332755.1, 3147049.097) in East and North respectively. I checked the prj file both of them are the same in the parameters with 0 transformation, but the results have 8cm and 6mm difference.

Could you check if this is a bug or used different projection method?

I'm looking forward to getting the answer, thanks mate

Cheers,