I’ve been looking at the current set of scans against the trig pillars database from nearby.
Most of the pillars seem to be out by around 80-130m with the scans typically being south and slightly to the west of the trig pillar. The deviation is fairly consistent across most of the country. I’m trying to see if the error varies in a simple way across the width of a scan.
It does seem to be smaller on the edge of the map nearest to the delamere trig point.
At the moment I can’t tell if the problem is one of a rotational difference (if the maps use a different north from the current OS north) or a more significant error in the Cassini Coordinate calculations.
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