FOI14586 – Request for information
Thank you for your email of 11 September 2015, requesting the following information in accordance with the Freedom of Information Act (FOIA) 2000:
1. The position, elevation, type, access requirements, current state and any other information held about triangulation stations, both current and disused, in machine readable form (CSV or equivalent).
2. To the extent that it is held, construction details of each type, specifically relating to any mounting points provided for survey equipment (dimensioned engineering drawings would be ideal).
I regret to inform you that Ordnance Survey is unable to help you with your enquiry as we do not hold this information.
However under our duty to provide advice and assistance as stipulated in Section 16 of the FOIA, we can provide the following explanation which may assist you in this matter.
The Trig Archive is considered a legacy database and is not one which is maintained. Ordnance Survey only holds a digital copy of the Trig Archive which I have attached. This includes limited details on each Trig station, however does include all Trig marks and not just pillars.
Full details are held in the (physical) office files for each Trig mark. Nearly all 32,000 (approximately) files are archived at The National Archives, the only exception being the Primary Pillars which are held in offsite storage on route to The National Archives.
I have also attached some diagrams (Zip file) showing the design of the three main types of Trig pillar - normal, circular and natural stone types.
We do not hold the technical drawings of the design of the 'spider', the brass 'forced centring' device set in the top of a trig pillar, however may be held at the National Archives.
The National Archives,
TW9 4DU.Tel: +44 (0) 20 8876 3444
Tel: 020 8876 3444
I hope the above is of use to you.
Your enquiry has been processed according to the Freedom of Information Act (FOIA) 2000. If you are unhappy with our response, you may request an internal review with our FOI Internal Review Officer, by contacting them as follows:
FOI Internal Review Officer
Customer Service Centre
Please include the reference number above. You may request an internal review where you believe Ordnance Survey has:
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Thank you for your enquiry.