Mapping Hacks

Extract a Spatial Model from Wikipedia #45

Chapter 4, Mapping (on) the Web

|

203

HACK

available for Linux distributions (you can get it in Debian by running apt-

get install graphviz

as root). The GraphViz Perl module allows us to easily

get at it programmatically.

Figure 4-18 shows the graph of a small section of Wikipedia’s spatial rela-

tions, centered on the UK. The graph of all spatial interconnections in Wiki-

pedia is too big for GraphViz to easily handle!

Hacking the Hack

You can use these techniques with any corpus of text that you have on a

disk somewhere, over which it might be useful to have a spatial index. A col-

lection of news articles or RSS feeds that you want to display on a map, or

old email archives to map project activity.

We chose to ignore pages whose titles were numbers. Collecting all pages

whose titles are four digits and/or that match the expression

/As of ^\d{4}$/,

you could build a pretty nice temporal index of Wikipedia. Imagine a map

where you adjust a knob and see local content and political boundaries

change through time. “As of” is a recent naming convention for dating pages,

sometimes used in different ways, and the temporal index probably won’t

reveal much depth yet, but Wikipedia is always growing and refining itself.

Figure 4-18. Graphing some of the spatial relations in Wikipedia