I have water level data for the Toronto Harbour that states, "74.200 metres above IGLD 1985"
I also have land elevation data around Toronto that uses the Geodetic Vertical Datum of 1928 (CGVD28)
To relate the two datasets I assume I need both sets of data using the same vertical datum.
How do I convert IGLD85 to CGVD28 for the area around the Toronto Harbour?