FOI14584 – Request for information
Thank you for your email of 3 September 2015, requesting the following information from Ordnance Survey in accordance with the Freedom of Information Act FOIA 2000:
1. Please can you explain how the OS system operated during the period 1948-1975 particularly with regards to mapping houses and all outbuildings in semi-rural settings, specifically our address.
2. How often were maps of our area redone during that period? What were the dates the maps were created and then published?
3. We would like to know how accurate the mapping was for each mapping episode for that period confirming the likelihood that the maps produced at each episode would detail every outbuilding.
4. Please can you confirm the date that the attached OS map/extract was “mapped” and published, the name suggests a date range of 19 years and a more specific date is required.
5. Please can you provide information that would explain why there are differences between outbuildings shown on conveyancing documents/deeds and the attached Ordnance Survey extract which has been sent to us by our local authority.
6. Please can you send us dated copies of extracts relating to our property/location for the years 1948, 1955, 1960, 1963 and 1971 (plus any intervening years where this information is held).
I can confirm that Ordnance Survey does hold some of the information you have requested to respond to your request. Where the information is not held, this is stated.
1. I can confirm that Ordnance Survey does hold this information. The map extract that accompanied your request for information is within the 1:2500 scale National Grid sheet SE1035. We know that this sheet was first published in 1965 and was based on survey work done in April 1964. This is when it was recast onto the national grid system from the earlier 1:2500 scale County Series mapping under the re-survey of Great Britain programme.
At the time of the re-survey in 1964 it will almost certainly have been visited on the ground by an Ordnance Survey surveyor who will have updated the map and surveyed all new features to the specification of the day. This states, and still does, that all permanent buildings and structures over eight square meters are required to be depicted true to scale in their correct position relative to surrounding detail.
After a map had been re-surveyed to the national grid system, Ordnance Survey policy was to update the master survey document for significant changes under the Continuous Revision programme. We would make microfilm copies of the master survey document periodically and republish as a new edition only when sufficient change had accumulated. This policy continued until the early 1990s.
2. I can confirm that Ordnance Survey does hold this information. The earlier 1:2500 scale County Series will have been originally produced in the latter part of the 19th century and then maintained sporadically after that date. It is very unlikely that any revision to this area on the County Series was done between 1948 and 1964 however we cannot say this definitively as we do not hold maps of this period. If they do exist then they will be found in the records of the national deposit libraries, contact details of which can be found on our historical map archives web page.
Surveys were carried out after the new sheet was surveyed in 1964 either under our continuous revision programme or at the request of the Land Registry. These changes can be seen on copies of the microfilms made in 1977, 1992 and 1993. No new edition of this sheet had been published up until the early 1990s when our policies changed once more.
3. I can confirm that Ordnance Survey does hold this information. For your address, the basic scale Ordnance Survey mapping has always been at 1:2500. Any outbuilding that did not meet the specification described in our answer to question 1 would not have been captured, regardless of when or by how the map was updated.
As for the accuracy of the mapping, this is constrained by the limitations of the scale and the manual plotting methods of the day. The relative accuracy of the local area will be very high with lines being plotted to an accuracy of around 0.4m at scale.
4. I can confirm that Ordnance Survey does hold this information. We believe that the map extract that you have provided is from the 1965 edition of Ordnance Survey 1:2500 sheet SE1035 which was surveyed in April 1964.
5. We do not hold this information because Ordnance Survey has not seen any “conveyancing documents/deeds” of the premises in question nor would we be able to comment on why any particular interpretation of our mapping may have been made by a third party.
6. I can confirm that Ordnance Survey does 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.
We do not hold information prior to the 1965 edition although you can view and download certain historic Ordnance Survey Maps on the Old maps website or visit one of the deposit libraries which can be found on the historical map archives web page.
We have found scans of the 1977, 1992 and 1993 microfilm copies (Zip file) referred to in question 2 which are attached.
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:
- Failed to respond to your request within the time limits (normally 20 working days)
- Failed to tell you whether or not we hold the information
- Failed to provide the information you have requested
- Failed to explain the reasons for refusing a request
- Failed to correctly apply an exemption or exception
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Thank you for your enquiry.