Air Survey and Data Change

We would appreciate the following information:

1. Would you please give the dates of the two air survey flights prior to October 2006 over the area referred to in our letter of 18th May 2011?

2. Can you also give details of the camera/cameras used in the four flights in question and the height at which the data was collected?

3. When the data from these flights is made available to HM Land Registry does the OS provide information as to where change has occurred in the data compared to previously available data?

4. Can you supply information on the internal accuracy of the current OS data sets? That is the the accuracy of separation of ground features given by the OS data sets and is not global or overall accuracy?

Thank you for your e-mail dated 5th August 2011, in relation to the land in your previous FOI request – FOI11167.We respond to each of your questions in turn, please note that some of the information is exempt and this is detailed where applicable.

1 & 2. Below is the air survey dates, height of capture and the cameras used to capture the information..

03/06/06, height unknown, film camera (type unknown flown by contractors)

09/06/06, height 7000ft, DMC digital camera

24/04/04, height 5000ft, 6” Leica RC20 6” film camera

17/04/03, height 1220m, 6” film camera (type unknown flown by contractors)

17/06/00, height 4500ft, 6” Leica RC30 film camera

27/04/96, height 8100ft, 12” Zeiss RMKA film camera

17/05/88, height 8100ft, film camera – but no model information held

3. Once the captured information is ingested in the product, Ordnance Survey does provide change only updates to HM Land Registry on a daily basis, which are automatically ingested in their systems.

However, this information does not highlight the specific changes which have occurred and HM Land registry do not hold a snapshot from one day to the next which would enable them to compare data.

4. This information is exempt under Section 21 of the FOIA ‘Information Accessible to applicant by other means’ as it is already published by Ordnance Survey on our website.

You may find this information by clicking on the link below, and viewing the table on page 15 of this document:

http://www.ordnancesurvey.co.uk/oswebsite/docs/user-guides/os-sitemap-user-guide.pdf

Your enquiry has been processed according to the Freedom of Information Act (FOIA) 2000. As all the requested information has been provided, or exemption by an absolute exemption, we have determined that in all the circumstances of this case the Public interest consideration (section 17 FOIA) is not applicable in this instance.

If you are unhappy with our response, you may raise an appeal to our Appeals Officer at:

FOI Appeals Officer
Customer Service Centre
Ordnance Survey
Adanac Drive
SOUTHAMPTON
SO16 0AS

Please include the reference number below. The Appeals Officer will ensure that the process has been followed correctly, questioning any decisions taken regarding the original response and recommending disclosure of additional information if appropriate.

Thank you for your enquiry.

Reference number: FOI11208/August 2011