Improved Tree Maps with R

“Treemaps display hierarchical (tree-structured) data as a set of nested rectangles. Each branch of the tree is given a rectangle, which is then tiled with smaller rectangles representing sub-branches. A leaf node’s rectangle has an area proportional to a specified dimension on the data. Often the leaf nodes are colored to show a separate dimension of …

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Mapping GCSE Scores

In the UK, August is exam results month for 16-18 year olds. Every year, photos of leaping teenagers clutching their results are accompanied by reports of record attainment rates, debates around how challenging modern exams are and, more so recently than ever, concerns for the number of sixth form and university places. Back in March …

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England Riots: Offences Committed and Offenders Age

The Guardian have been keeping track of the magistrate cases and convictions resulting from the recent rioting in England. Using this data I have produced the “tree map” below. For each magistrate I have grouped each offence committed and represented it as a square. The size of the square represents the number of people who …

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Contouring Data

It’s been a while since I did any Fortran. I’ve been looking into contouring algorithms and decided to have a look at Paul Bourke’s Conrec program that was originally published in Byte magazine in 1987: http://paulbourke.net/papers/conrec The graph above shows the underlying data values as a coloured square grid with the black contour lines on […]

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Exploring the Historical Determinants of Urban Growth Patterns through Cellular Automata

Kiril Stanilov has adapted RIKS METRONAMICA, an established cellular automata (CA) modelling system, to simulate the historical growth of a section of a large world city. The focus is on simulating change from the late 19th century until the modern …

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Weather Underground

I’ve been looking at the Weather Underground API (http://wiki.wunderground.com/index.php/API_-_XML) which gives access to the observation stations and the data they are collecting. The API uses simple commands to query for a list of stations, for example: http://api.wunderground.com/auto/wui/geo/GeoLookupXML/index.xml?query=london,united+kingdom Using C# and .net, this is accomplished as follows: WebRequest request = WebRequest.Create(string.Format(GeoLookupXML, @”london,united+kingdom”)); HttpWebResponse response = (HttpWebResponse)request.GetResponse(); XmlDocument […]

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Network Population Density for Southwark

Using the excellent SANET extension for ArcGIS 9.3 I was able to take some of my data for Southwark that I had geocoded to address level, and estimate the population density using the OS Mastermap ITN product. The procedure is essentially a Kernel Density Estimation that takes place on a given network rather than across 2D space, this effectively controls […]

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