Estimate the parameters of 3D similarity transformation (Helmert) in Matlab / Octave using the Geodetic Transformations Toolbox with geographical coordinates as input and a PROJ4 string / PROJ pipeline as output.
- Download and Install Matlab (commercial sorftare) or Octave (free software)
- Download the Geodetic Transformations Toolbox by Peter Wasmeier (license)
- Download simtrans3Dgeo.m (and if you are using Octave also pad.m) from this repository
- Create a script like Krayenhoff2ETRS89eersteorde.m with your input and run it
- Identify and deselect outliers in the residuals and re-run the script
- Copy the PROJ4 string (e.g. for a custom CRS in QGIS) or the PROJ pipeline (e.g. for transformation with cct in PROJ) from the output