‘More or Less‘ is a good programme on BBC Radio 4. Regularly exploring the numbers and the evidence behind news stories and other important things, and checking if they stand out. However, the piece that was broadcast this week about Golf courses and housing in the UK provides a nice demonstration of when not to use crowdsourced information. The issue that was discussed was how much actual space golf courses occupy, when compared to space that is used for housing. All was well, until they announced in the piece the use of clever software (read GIS) with a statistical superhero to do the analysis. Interestingly, the data that was used for the analysis was OpenStreetMap – and because the news item was about Surrey, they started doing the analysis with it.
For the analysis to be correct, you need to assume that all the building polygons in OpenStreetMap…
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