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We are attempting to reproject several raster and vector datasets from GCS_GRS_1980 to WGS_1984_Web_Mercator_Auxiliary_Sphere. I have tried a several different transformations but each time there is a noticeable shift in the data. Does anyone know the correct transformation to use? Our data is mostly in the SE United States, mainly Georgia, South Carolina, & North Carolina. We also have a few datasets that span the entire USA.
I'm having the same problem determining the correct transformation from state plane (GA FT, SC Int FT, & NC FT) to web mercator. Any ideas?
Thank you very much in advance!
I assume, because they're state plane, that the geographic coordinate systems are either NAD 1983 or NAD 1983 HARN (or both). Any NAD83 / WGS84 transformation should do minimal to no shifting, depending on which one is used. At worst, in that part of the country, they should differ by no more than a meter. Are you seeing shifts larger than that?
NAD_1983_To_WGS_1984_1 is a null transformation (parameters are zeroes). It assumes NAD 1983 and WGS 1984 are equivalent. That isn't true any more, so a more current transformation, NAD_1983_To_WGS_1984_5, does try to compensate for the current differences.
NAD_1983_HARN_To_WGS_1984 is another null transformation.
WGS_1984_(ITRF00)_To_NAD_1983_HARN is similar to NAD_1983_To_WGS_1984_5.