About this website
This website provides interactive mapping of outstanding residential mortgage lending by postcode sector across Great Britain, as published by individual banks, via the Council of Mortgage Lenders. This first iteration of the website - published in January 2014 - uses the most recent bank lending data, which covers the period up to the end of June 2013. I hope to update the website with future data releases, if I have the time. The map is coloured so that there are roughly the same number of areas in each category displayed in the key to the right. It's important to remember that this data release covers only seven major lenders and about three quarters of the mortgage market - it is not the full story but it does give us interesting insights that were previously not possible. The release did not include mortgage lending data for Northern Ireland, so that's why it's not included here. I've included a large interactive map on the home page and if you click below that you can see a full screen map. I've also added in some tabs which show postcode sectors in and around London, Glasgow, Manchester and Cardiff but if you want to find somewhere else you can easily pan and zoom to it via the big map.

The site will work best on a modern browser such as recent versions of Safari, Chrome or Firefox. Users may experience some problems with older versions of Internet Explorer (version 8 or earlier) - for example, the charts might not display in the info window when you click on the map.

Who made this site, and why?
This site was created by Alasdair Rae, a senior lecturer at the University of Sheffield. I made this website for three main reasons - 1. to test how this new data source on mortgage lending could be shared and visualised in a map-based platform; 2. to let people explore the data geographically rather than having to look through the various spreadsheets of data; 3. to allow users to examine the mix of lending sources in local areas. It's also a good demonstration of the power of Google's Fusion Tables for quick and relatively easy display of large spatial datasets. 

I made the site by modifying a template I developed previously in Google Sites. I've done this kind of thing before for a range of different datasets, of which you can read more on my blog. One of my newer areas of research is about housing markets and another more longstanding interest is mapping and spatial technologies, so I've combined the two to create this site. If you want to find out more about my work, including academic papers I have published, you can do so via this page. I also often tweet about my work so if you're into that kind of thing click the image below.

Technical information
I created the maps on this website using Google Fusion Tables, a relatively new (and experimental) Google technology which is available to anyone with a Google account. It allows users - and mapping specialists - to easily and simply create shareable, interactive maps overlaid on top of the standard Google Maps interface. If you're a relatively experienced GIS user and you are good with data then you might find it worth your while exploring how to produce maps in this way. Take a look at an entry from my blog as a starting point if you want to find out more. For further details on how to get charts in the info windows (that is, the little pop up bubble you see when you click the map) see this entry from my blog. 

More generally I recommend that if you want to get into this you start off by looking at the Fusion Tables help pages. If you're developing a map using Fusion Tables and you want to know how I did the little bar charts in the info windows on this site, get in touch and I'll explain.

The site itself is based on Google Sites. As you can see, I've tried to keep it as simple as possible.

Data attribution and sources
As I've said above, this data was released via the Council of Mortgage Lenders and they really do a great job of summarising and explaining it on their website. I had to do a bit of digging to find the Barclays lending data because at the time of putting this together it wasn't linked to directly from the Council of Mortgage Lenders website but it can be found here

The only other thing to say is that HSBC were the only bank to publish their data in a PDF, which was highly inconvenient for the purpose of analysis. However, I extracted it from the PDF by using the very nice Tabula tool, which to my knowledge is the best one out there for getting tables out of a PDF and into a spreadsheet.

The data on the number of households in each postcode area came from the 2011 Census in England and Wales and the 2011 Census in Scotland. The Scottish Census data is © Crown copyright and the data are supplied by National Records of Scotland. The data for England and Wales is also  © Crown copyright and was sourced via the Office for National Statistics.

The postcode sector boundaries were sourced from the wonderful GeoLytix who have, to my knowledge, the best set of open data postcode sector boundaries currently available.