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OS Maps

Request for information - Ref No: FOI18818

Request

Thank you for your email of 8 March 2018 requesting information from Ordnance Survey in accordance with the Freedom of Information Act (FOIA) 2000, as set out in the extract below:

1. Please advise which sources routinely provide information to compile or amend your online mapping in the Wigan area at each 'zoom-in' level; how you access this information, and with what frequency.

2. Please confirm what records you hold showing the sources of information used, including but not exclusively access to electronic mapping and aerial photography, to amend your online map at each 'zoom-in' level, in relation to the vicinity of and including Byrom Hall in Lowton between, and including, 2011 to 2014.

3. Please confirm the dates of when any aerial photography was used over this location between 2001 and 2014 and provide copies of any images captured.

4. Please confirm when any visits or surveys were undertaken in this area between 2001 and 2014, and provide copies of any amendments made to the map in this area.

5. I am particularly interested in receiving copies of any recorded information you hold relating to the reason and date that resulted in the mile-long circular path around the open access area known locally as Byrom Wood - which was laid when the wood was planted around 2002, being amended by you to show the path terminating approximately half way round the woodland area on your online map. I could understand it if there was no path at all shown on the map, but when the path was laid all in one go and still exists to this day, how can a map just show half a path?

6. I am also interested in any information relating to why, when you zoom right in, the boundary of the original '22 plus' acres of woodland has been reduced in size and the outline amended to give a totally inaccurate boundary.

7. Please advise what quality control procedures should have been applicable at each zoom level, and provide copies of recorded information to confirm whether these procedures were fully complied with on any occasion between 2011 and 2014 when changes were applied to the particular map area which includes Byrom Wood.

Our response

I confirm that Ordnance Survey does hold some of the information you have requested. Where the information is not held this is stated. Taking each request in turn, I confirm the following:

1. Please advise which sources routinely provide information to compile or amend your online mapping in the Wigan area at each 'zoom-in' level; how you access this information, and with what frequency.
Whilst this does not appear to be a valid request for information held in a recorded form under section 8 of the FOIA but a general enquiry, we are able to provide the following information in accordance with our duty under section 16 of the FOIA to provide advice and assistance.

OS Maps is the interactive mapping facility for both website and mobile platforms that provides access to Ordnance Survey maps online, as well as other benefits (‘OS Maps’).

OS Maps is compiled from several Ordnance Survey (‘OS’) mapping products. Certain map products are displayed at different zoom levels. This enables users to view a zoomable range from the lowest (i.e. least detailed) zoom level 7, to the highest (i.e. most detailed) zoom levels 16-18. Certain mapping products are only accessible to users with paid subscriptions to OS Maps.

Each mapping product displayed within the OS Maps online facility is updated according to its own update cycle for that product, and not all the products within the OS Maps facility are updated at the same time.

Ultimately, each product displayed on OS Maps is amended using information sourced from Ordnance Survey’s most detailed mapping product: the OS MasterMap Topography Layer (‘OSMM Topo’). OSMM Topo is itself in turn updated using a variety of sources, including ground surveys, aerial imagery and third party data, according to a cyclic revision process. Details of such process have previously been provided to you in our response dated 29 January 2018 (FOI17805).

The table below details which OS product is displayed at each zoom level depending on the type of access (either standard or subscription access) together with a link that shows the update frequency and further information about each OS product on the OS website.

Zoom LevelOS map productStandard or Subscription accessWeblink for further information and update frequency
16-18OS Vector Map LocalStandard

www.os.uk/business-and-government/products/vectormap-local.html

13-15OS Vector Map DistrictStandardwww.os.uk/business-and-government/products/vectormap-district.html
7-12StategiStandard

www.os.uk/business-and-government/help-and-support/products/strategi.html

7-11MiniscaleSubscription

www.os.uk/business-and-government/products/miniscale.html

12-131:250 000 Scale Colour RasterSubscription

www.os.uk/business-and-government/products/250k-raster.html

14-151:50 000 Scale Colour RasterSubscription

www.os.uk/business-and-government/products/50k-raster.html

16-181:25 000 Scale Colour RasterSubscription

www.os.uk/business-and-government/products/25k-raster.html

You can find further information relating to the OS Maps zoomable mapping stack and its functionality on our OS Maps quick start guide page.

2. Please confirm what records you hold showing the sources of information used, including but not exclusively access to electronic mapping and aerial photography, to amend your online map at each 'zoom-in' level, in relation to the vicinity of and including Byrom Hall in Lowton between, and including, 2011 to 2014.
Please see our responses to questions 3 and 4 below which detail the updates made to the area you refer to in your request.

As explained in the response to question 1, the source data used to make changes to the products displayed in OS Maps is the OSMM Topo. Once changes have been made to this product the changes are then filtered through to the other OS products in accordance with their revision policy. OS Maps shows the OS products depending on the zoom level and type of access as shown in the table above.

3. Please confirm the dates of when any aerial photography was used over this location between 2001 and 2014 and provide copies of any images captured.
I can confirm that aerial imagery for the area that you refer to was captured by Ordnance Survey when the area was flown in 2006 (on 24/07/2006), 2009 (on 10/09/2009) and 2013 (on 04/11/2013).

I can confirm that the aerial imagery captured in 2013 was used to update OSMM Topo for the area in 2014, and that the imagery captured in 2009 was used to update the mapping Layer for the wider area over the location in 2010, in both cases as part of the cyclical revision process for OSMM Topo.

Although the area was flown in 2006, I am unable to confirm that the aerial imagery captured then was used to update OSMM Topo as we have no records to confirm this, however it is likely that the updates in 2006 were from imagery.

I can confirm that the area has also been flown at different times by an external supplier in 2005, 2007 and 2010 but there are no records to show that such aerial imagery has been used in OS mapping products, and nor do we hold copies of such imagery.

A disc has been sent out to you today by first class post with the aerial photographs requested.

Please note that these documents (and also those provided to you in response to question 4) are subject to Crown copyright. Therefore, you may not reproduce, distribute or publish any of them without Ordnance Survey’s express permission. This restriction does not apply to reasonable use for your own non-commercial research purposes, private study, or any other uses permitted under the Copyright, Designs and Patents Act 1988.

Please see our response to question 4 which details when amendments to the mapping in the area were made from imagery.

4. Please confirm when any visits or surveys were undertaken in this area between 2001 and 2014, and provide copies of any amendments made to the map in this area.
I can confirm that Ordnance Survey has not carried out any field surveys in the area you refer to between 2001 and 2014. Please see my response to question 3 which confirms the years in which the area was flown for the same period to capture aerial imagery photography.

I am able to provide you with copies of OSMM Topo which shows that OSMM Topo has been amended 3 times for the area you refer to in your request during the period between 2001 and 2014. Please refer to the attachments which show the following information:

  • 2006: Part of the path is added to the data
  • 2010: Part of the wood is added to the data
  • 2014: Remainder of the wood is added to the data

I have also included a copy of the map from 2005 which depicts the area in OS mapping before 2006 (and which has been unchanged since at least the early 1990s) for reference purposes.

5. I am particularly interested in receiving copies of any recorded information you hold relating to the reason and date that resulted in the mile-long circular path around the open access area known locally as Byrom Wood - which was laid when the wood was planted around 2002, being amended by you to show the path terminating approximately half way round the woodland area on your online map. I could understand it if there was no path at all shown on the map, but when the path was laid all in one go and still exists to this day, how can a map just show half a path?
I can confirm part of the path you refer to in your request was captured in our data in 2006, and that in 2017 the path was updated in OSMM Topo to show the full extent.

I can confirm that Ordnance Survey does not hold any information in relation to ‘why’ only part of the path was captured in 2006. The map itself is the only record kept. I am therefore unable to comment on the detail of specific features shown on the mapping or provide reasons for why or how a feature is shown on the map.

As described above in our response to question 1, when viewing OS Maps and ‘zooming’ through the scales different OS mapping products can be seen depending on the zoom level and type of access that you have for the application (standard or premium). The OS map products at the higher zoom level, OS Vector Map District (‘OS VMD’) and OS Vector Map Local (‘OS VML’), have, as of yet, not been updated to reflect the changes to the path made in 2017 that are now included in OSMM Topo, due to the revision schedules for those OS map products. Therefore although only part of the path is currently displayed on OS Maps at the higher zoom levels (for OS VMD and OS VML), the full extent of the perimeter path for Byrom Wood can be seen at other levels in the products accessible in OS Maps via the subscription access.

Ordnance Survey is currently working towards ensuring that its data and products are aligned. We are currently in the process of updating the OS products for this area as detailed in our response dated 29 January 2018 (FOI17805). Ordnance Survey aims to have OS Maps showing the full extent of the woodland and footpath, at all zoom levels, once the changes have filtered through to OS VMD and OS VML later this year.

I note this point has been previously answered in our response to you dated 29 January 2018 (FOI17805) and has been previously addressed by Ordnance Survey’s Customer Service Centre.

6. I am also interested in any information relating to why, when you zoom right in, the boundary of the original '22 plus' acres of woodland has been reduced in size and the outline amended to give a totally inaccurate boundary.
I can confirm that when viewing OS Maps, the OS products in the standard access mode at the highest zoom levels (zoom levels 16- 18, showing OS VML) have not been updated to reflect the changes made in 2014, when the full extent of the woodland was added to our data in accordance with our revision schedules. Therefore, when viewing at the higher zoom level, OS Maps still currently only shows part of the woodland. I can confirm the woodland is now depicted correctly in OSMM Topo and in other products in OS Maps, but that the OS VML product is due to be updated shortly to depict the full extent of the woodland. Please see our response to question 5.

I note this point has been previously answered in our response to you dated 29 January 2018 (FOI17805) and has also been previously addressed by Ordnance Survey’s Customer Service Centre.

7. Please advise what quality control procedures should have been applicable at each zoom level, and provide copies of recorded information to confirm whether these procedures were fully complied with on any occasion between 2011 and 2014 when changes were applied to the particular map area which includes Byrom Wood.
The first part of your request asks us to ‘advise what quality control procedures should have been applicable at each zoom level’. Whilst we consider that the first part of your request does not appear to be a valid request for information held in a recorded form, we provide the following information in accordance with our duty under section 16 of the FOIA to provide advice and assistance.

In relation to the first part of your request, this question is substantially the same as those answered in our response to you dated 29 January 2018 (FOI17805: Q2 and Q7). We therefore consider this to be a repeated request under section 14(2) of the FOIA.

However, to further clarify I confirm that quality control is undertaken for all OS products used for OS Maps. There is no additional quality control in place in terms of the display of such products in OS Maps, other than visually ensuring the new data has successfully loaded and rendered.

As explained above, the OS products that can be seen via the OS Maps application depend on the zoom level in which they are viewed and the access type (standard or premium).

For Byrom Wood, the quality control procedures for each OS product depending on the zoom level in OS Maps is as follows:

The OS products accessible in the standard access to the OS Maps application (that is Strategi, OS VML and OS VMD) are based on Vector data, and as such the quality checking procedures in place are to ensure that the data quality and geometry is accurate, rather than the depiction of specific features for quality assurance purposes. As stated previously, these products contain data that is generalised from OSMM Topo data, and it is at the OSMM Topo level that quality controls as to the geographical representation of the features on the map apply.

  • For OS VML, quality check procedures are applied in a ‘revision flowline’ for updating or revising individual VML mapping tiles. The VML tiles chosen for the revision flowline process are determined according to the following Quality Control/Quality Assurance Assessment Criteria: (i) density of revision; (ii) completeness of revision; and (iii) errors from previous edition. A full quality control check will be carried out on only around 10% of individual VML mapping tiles in the revision flowline process. This quality control includes printing selected individual VML tiles, which are then visually assessed against large scale (i.e. more detailed mapping) data (from OSMM Topo). Any notes or remarks made on the print out are then passed to an editor to make on screen edits of the VML tiles, which are then saved and stored for the product refresh. The printed plots are then shredded and recycled immediately after use. By contrast, a quality assurance procedure is applied to the remaining 90% of VML mapping tiles in a revision flowline. The quality assurance procedure involves change detection and then edits to any geometric or other validations required against the VML product specification. Any tiles that have been updated in the revision flowline replace the corresponding tile for the next product refresh.

  • For OS VMD, the quality control procedure is carried out according to a revision process that is scheduled to coincide with the update frequency for the OS VMD product, and currently occurs twice per year. The revision process for the OS VMD tiles are validation checks (not visual checks) to confirm that the geometry is valid following generalisation of the data. Once these edit jobs have been completed, the product output run is commenced and any tiles that have been edited will replace the corresponding tile for the next product refresh.

  • For the Strategi product no details are provided for the quality control procedures. I can confirm that the Byrom Wood area is too small to be within the scope of the specification for this product. Accordingly, Byrom Woods is not depicted in the zoom levels at the scale in which the Strategi Product is shown on OS Maps.

  • For the Miniscale and 1:250,000 scale colour raster products, no quality control procedures are provided because Byrom Wood would not be visible on these products and therefore it is not within the scope of the question to provide the procedures for these products.

    In relation to the OS Products that are visible on the zoomable layers in OS Maps when viewed in the subscription access mode, the quality control procedures for the 1:25,000 and 1:50,000 scale OS products are as previously advised in our response to you dated 29 January 2018 (FOI17805: Q2 and Q7).

    In relation to the second part of your request to ‘provide copies of recorded information to confirm whether these procedures were fully complied with between 2011 and 2014 when changes were applied’, I can therefore confirm Ordnance Survey does not hold this information for either the quality control or assurance procedures for each OS product. Any quality control or assurance procedures are carried out on temporary files or printed paper plots and these are deleted or destroyed after use.

    In addition, I can confirm that there is no information held to confirm that any quality control or assurance procedures were complied with in relation to the visual rendering and loading of the products for the purpose of their display within the OS Maps application, because OS does not retain records of these processes.

Internal review

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 Internal Review Officer by contacting them, within two months of receipt of our final response to your FOI request, as follows:

Internal Review Officer
Customer Service Centre
Ordnance Survey
Adanac Drive
Southampton
SO16 0AS
E-mail: foi@os.uk

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

The Internal Review Officer will not have been involved in the original decision. They will conduct an independent internal review and will inform you of the outcome of the review normally within 20 working days, but exceptionally within 40 working days, in line with the Information Commissioner’s guidance.

The Internal Review Officer will either: uphold the original decision, provide an additional explanation of the exemption/s applied or release further information, if it is considered appropriate to do so.

Appeal to Information Commissioner's Office (ICO)

If, following the outcome of the internal review you remain unhappy with our response, you may raise an appeal, within three months of receiving our response, with the Information Commissioner’s Office. Further information can be found on the ICO website (ico.org.uk) under ‘Report a concern’ or you may wish to call the ICO helpline on 0303 123 1113.

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