Saturday, November 28, 2015

UK house price data for October 2015

I’ve uploaded the latest Land Registry house sale data for England and Wales to my website.

Tuesday, November 24, 2015

Postcode data for November 2015

I’ve uploaded the latest ONS postcode data for November 2015 to my website, all 2,554,806 of them. I’ve run my usual checks but let me know if you spot anything that looks incorrect.

Sunday, November 22, 2015

Fixing Strava elevation data

For some reason, Strava actually trust the data that comes from their users. More specifically they use the elevation data from the user’s ride when the user creates a segment. From a technical point of view, this is definitely the easiest thing to do, but unfortunately GPS devices do occasionally lose their mind, so the data can be a mess. This can lead to garbage segment data, like this. A glance at the elevation profile makes it obvious that something is amiss. This dodgy data then means any derived data is also dubious, such as the climb category and the VAM numbers. The KOM rider on this particular segment has a VAM of 9,992 which is over 5 times what a drugged up Lance Armstrong could achieve. Even my average VAM on category 4 climbs is over 1,000 which suggests I could make a good fist of keeping up with a bunch of professional cyclists. Which I couldn’t. Ever.
In an ideal world, Strava would fix up these dodgy segments in some way. One fix would be to average out all the elevation data from every rider who has ridden a segment. Alternatively, they could use the elevation data from one of the mapping services. Finally, they could make it easier to report bad data.
So whilst we wait for Strava to fix this issue, I thought I’d have a play with the second option. My Strava segment search tool now has the ability to view segments as well as view them on Strava. This is what the example segment looks like. It use Google Maps to calculate the elevation of the segment and adds that to the elevation profile, along with calculated statistics.

Monday, November 09, 2015

UK stations data

As a prelude to some other work I might one day get round to, I’ve uploaded a list of UK train stations to my website. It comes in CSV and KML flavours, with the KML highlighting the busiest stations (mostly in the South East, as if you need to ask).