A quick run down of frequently asked questions

How do I licence OpenPopGrid?

OpenPopGrid is an open dataset which you are free to use under the terms of the OdBL licence and provided that data are cited as follows:

Text Citation:
Murdock, A.P., Harfoot, A.J.P., Martin, D., Cockings, S. and Hill, C. (2015) OpenPopGrid: an open gridded population dataset for England and Wales. GeoData, University of Southampton.

Mapping Citation:
© OpenPopGrid, 2015. This product contains information from several Information Providers under Open Government Licence and Ordnance Survey OpenData Licence (http://openpopgrid.geodata.soton.ac.uk /Openpopgrid.xml)

Third Party Data Acknowledgements:
The development of OpenPopGrid has utilised the following datasets supplied under the Open Government Licence and Ordnance Survey OpenData Licence.

  • Ordnance Survey - VectorMap District, © Crown copyright and database right 2014
  • Office for National Statistics - 2011 Census Output Area boundaries, 2011 Census Postcode headcounts © Crown copyright and database right 2014
  • Office for National Statistics - ONS Postcode Directory (Open) May 2011 © Crown copyright and database right 2014, © Royal Mail copyright and database right 2014

If I register, how will you use my information?

The information which you provide on registering to download the data will be used to help us understand the types of organization and use cases that OpenPopGrid is being used for. You will have the option to be added to our mailing list to find out about future enhancements to the datasets and OpenPopGrid events. However, you must provide a valid email address to receive download links.

Can I use OpenPopGrid on commercial projects?

Yes. The data are available for commercial use and re-use provided that the citation is made.

How accurate is OpenPopGrid?

This is quite a complex question as it relies on having a definitive high resolution population dataset to compare to and which gives the best estimate of how many people are living in an area. The full set of household-level locations and population counts collected at the time of the 2011 census is a highly confidential dataset held securely by the Office for National Statistics and not available for validation purposes. We are currently working on various means of validating the estimated counts at the small area level as the basis for producing further accuracy measures.

Having said that, our processing workflows are designed to ensure that OpenPopGrid honours published Census Output Area totals, when aggregated to this level. Our validation has shown that overall OpenPopGrid has a mean difference from the OA total of 0.01 people. In 99.1% of cases the difference is less than 0.001 and with a maximum difference of 43.

We would like to improve the accuracy of OpenPopGrid with regard to the removal of more non-residential buildings (e.g. schools). However, OpenPopGrid relies solely on Open Datasets and a definitive high resolution buildings classification for the UK does not currently exist. We are exploring the possibilities of using components of other open datasets such as OpenStreetMap to remove non-residential buildings from the candidate cells.

Why did you not use a higher resolution building input such as OS StreetView OpenData?

It would have been possible to use more detailed building objects extracted from the OS StreetView dataset but it was felt that the OSVMD data provided the indicative shapes of the buildings and would be more suitable for mapping and analysis over larger areas.

What do I need to be able to use OpenPopGrid

The ASCII grid format is a raster data format stored in plain text. As text, the files can be viewed in a text editor, or in a spreadsheet package, using a space delimiter to import it, however the data is best explored in GIS software. The format is widely supported by GIS software, including ArcGIS, QGIS and MapInfo and can either be viewed directly or translated into other formats.

A raster dataset stores data values recorded at regular intervals over a rectangular area. For OpenPopGrid, the data interval is 10m, and each download file covers a different 100km square of England and Wales. Hence each download file will contain data values in a grid of 10,000 rows by 10,000 columns. The data is stored in rows with each value separated from its neighbour by a space. Not all grid cells contain population, so a no data value is defined to reflect this. In the OpenPopGrid data, this is -9999. Any data values other than this are the population of the grid cell as estimated by OpenPopGrid.

Do you have any plans for a full UK Coverage?

We are currently running Scotland and looking into the inclusion of Northern Ireland which has slightly different data inputs. Keep an eye on the website and our Twitter feed for more details.

How do I know which files to download for my area of interest

On launch we are providing the data cut to the Ordnance Survey 100x100k grid tiles and which are denoted with different letters (e.g. SU, TQ etc). If you look at the map on the download page you can choose which area(s) you wish to download.

We are also currently working on a web download site where you can create a more specific Area of Interest (AOI) for the data you wish to download. We will also make the data available as a static backdrop web service. Both of these services should be available soon but keep an eye on the website and emails for further announcements.

How do we report issues / feedback on the dataset

Please send any queries or any issues about the dataset to openpopgrid@geodata.soton.ac.uk

We are also asking people to tell us what they think about the dataset so would encourage you to fill out the feedback form where you can help set future direction for the product.

Do I need to provide an acknowledgement for the dataset when I build an application or website that uses OpenPopGrid.

Yes. Please provide a citation to OpenPopGrid in reports and on mapping as stated in "How do I licence OpenPopGrid" above.