Alex Singleton

Professor of Geographic Information Science at the University of Liverpool

© 2014. Alex Singleton All rights reserved. About my blog code

Geodemographics and the Internal Structure of Cities

Seminar given at Cardiff University on 16/12/14.

Big Data in the Real World

Seminar given at UCL on 2/12/14.

e-Resilience of British Retail Centres

Short talk given at Nottingham Business School, ESRC KEO Event 27/11/14.

QMRG Committee Timeline

Quite a long time ago I spent considerable hours trawling through QMRG reports that featured in old issues of Area and Transactions of the Institute of British Geographers to examine how the committee had evolved over time. In these pre R days, I assembled these into a spreadsheet (sorry!) of both the report text, and also as a timeline. You can download both of these files on the github repository.

These files have sat on my machine for years, however, I thought they would make a nice addition to the new combined QMRG and GIScRG website - Quantile. As such, I have generate a D3 timeline of the committee membership, and assembled a chronology of events - the code is also on github here.

I would not claim that this is comprehensive, and only features those entries gathered from the reports. If you were involved in the committee and are missing, or the dates are not quite correct, then let me know.

View the timeline here


Simplify a Shapefile with Mapshaper on OSX

Yesterday I needed to simplify a shapefile quite substantially to get the size down enough that it could be loaded into CartoDB. Using QGIS this tended to leave sliver or gaps between polygons, but I came across Mapshaper. This is primarily a command line tool and is built on node.js. However, a web version also exists. There are a load really useful GIS functions such as simplifying, clipping, dissolve, joins and merges.

Using Mapshaper on OSX

From install to use (including node.js) was about two minutes...

The first step is to install node.js; visit the website and download the package by clicking the install button on the homepage. Run the install and follow through the instructions. This will install node.js on your computer - this is a platform built on Chrome's JavaScript runtime for developing applications. Node.js is cropping up in lots of new applications - for example, the new blogging system Ghost.


After install of node.js, you need to install Mapshaper which can be done by running the following on the terminal:

npm install -g mapshaper

If you get an error about permissions when running the above, you might have to preface the command with sudo (which will ask you for a password):

sudo npm install -g mapshaper

After this you are done. In my case, I was interested in simplifying a shapefile (located in my Dropbox) which I could complete with the following command (the % are the percentage of removable points to retain). The first shapefile listed is the input, and the second the desired output.

mapshaper /Users/alex/Dropbox/US_tract_clusters_new.shp -simplify 1% -o /Users/alex/Dropbox/US_tract_clusters_new_05pct.shp

Examples of the output:

Original Shapefile

Simplified Shapefile

Thanks to the developers.

The Geodemographics of Use and Engagement with the Internet

Talk at the Market Research Society, London; 5/11/14.