[Talk-GB] Possible use of OS triangulation stations to determine aerial imagery offset

Greg gregrs at fastmail.co.uk
Tue Aug 16 14:22:11 UTC 2016


Dear all,

Ordnance Survey has a database of triangulation stations and their
precise locations as OSGB36 (National Grid) co-ordinates publicly
available here:
https://www.ordnancesurvey.co.uk/gps/legacy-control-information/triangulation-stations.
There is also a FOI request with a full CSV file here:
https://www.ordnancesurvey.co.uk/about/governance/foi/questions/2015/0056.html.
I'm not sure under what licence the co-ordinates are published though.

It struck me that accurate co-ordinates for the visible stations such as
church spires, masts and water towers could be helpful in accurately
determining the offset of aerial imagery. It's possible to convert the
CSV to a GPX file with WGS84 lat/lon using QGIS (although I couldn't get
JOSM to display the metadata for each point). The imagery can then be
aligned to these points, bearing in mind of course that the imagery is
often taken from an angle (see
http://wiki.openstreetmap.org/wiki/Roof_modelling#Drawing_of_simple_building_outlines).

Best wishes,
Greg.



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