I wonder if you can point to me which department should I askto for the coordinates of Control Points or in general for the standards used by TFL when georeferencing projects done for this authority.

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TfL Ref: FOI-1741-1920

Thank you for your email received by Transport for London (TfL) on 9 September 2019, asking for the coordinates of control points.

Your request has been considered in accordance with the requirements of the Freedom of Information (FOI) Act and our information access policy.  I can confirm we do hold the information you require.

Unfortunately, to provide the information you have requested would exceed the ‘appropriate limit’ of £450 set by the Freedom of Information (Appropriate Limit and Fees) Regulations 2004.

Under section 12 of the FOI Act, we are not obliged to comply with a request if we estimate that the cost of determining whether we hold the information, locating and retrieving it and extracting it from other information would exceed the appropriate limit. This is calculated at £25 per hour for every hour spent on the activities described.

We have estimated that it would considerably exceed the cost limit to provide a response to your current request.

There are a large number of control points in our stations, tunnels and highway. We also use Ordnance Survey Grid for certain projects; mainly highway related where they interface with the local authorities.

We have three levels of control; primary, which is a small number of points, and we have no concerns about releasing these. And then there are secondary and third order points which total around 10,000 points. Many of them are in secure areas. There are very large numbers of both of these with no consistency of application. This means that releasing the information on either of these sets would be effectively releasing the full three dimensional positioning which would constitute security sensitive information and should be exempt from disclosure under Section 38(1)(b) of the FOI Act. Disclosure of the exact locations of stations and tunnels in three dimensions could be obtained and utilised by individuals who may wish to use this technical information to cause disruption or harm to the London Underground network. Therefore, to work through these sets of control points one by one to remove those in secure areas, would be a very time consuming task.

To help bring the cost of responding to your request within the £450 limit, you may wish to consider narrowing its scope so that we can more easily locate, retrieve and extract the information you are seeking. You should identify the information that you want as clearly and concisely as you can, specifying the types of document that you are looking for. You might also consider limiting your request to a particular geographical area so that we can supply only primary control points that you are the most interested in.

Please note that we will not be taking further action until we receive your revised request.

In the meantime, if you have any queries or would like to discuss your request, please do not hesitate to contact me.

Please see the attached information sheet for details of your right to appeal.

Yours sincerely

Eva Hextall

FOI Case Officer

FOI Case Management Team

General Counsel

Transport for London

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