I have a series of raster maps of geophysics for an archaeological site in Turkey. These are ostensibly in UTM zone 35, WGS84 projection, but the surveyors set their grid with a total station using a slightly different coordinate for our local datum than the one we use, 1.726 m to the W and 0.735 m to the S. So when I bring them into QGIS 3.18 with the data for the site as a whole, they end up shifted a couple meters to the SW. What is the easiest way to bring them all into alignment with the rest of the system?
I naively tried creating a custom projection with a small offset (like post Shift a CRS by an observed offset) by adding 1.726 to the false easting and 0.735 to the false northing of the project CRS 32635, so:
PROJCRS["GeoIm 2018", BASEGEOGCRS["WGS 84", DATUM["World Geodetic System 1984", ELLIPSOID["WGS 84",6378137,298.257223563, LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0, ANGLEUNIT["degree",0.0174532925199433]], ID["EPSG",4326]], CONVERSION["unnamed", METHOD["Transverse Mercator", ID["EPSG",9807]], PARAMETER["Latitude of natural origin",0, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8801]], PARAMETER["Longitude of natural origin",27, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8802]], PARAMETER["Scale factor at natural origin",0.9996, SCALEUNIT["unity",1], ID["EPSG",8805]], PARAMETER["False easting",50001.726, LENGTHUNIT["metre",1], ID["EPSG",8806]], PARAMETER["False northing",0.735, LENGTHUNIT["metre",1], ID["EPSG",8807]]], CS[Cartesian,2], AXIS["easting",east, ORDER[1], LENGTHUNIT["metre",1, ID["EPSG",9001]]], AXIS["northing",north, ORDER[2], LENGTHUNIT["metre",1, ID["EPSG",9001]]]] This however shifts a test raster by about 450000 m to the east. I'm obviously flailing here; can someone point me in the right direction? Since I will be getting more data from these folks in the future, it seems better to somehow recognize their system than manually move every raster by a given amount.
