Squartasrophe! Squarpocalypse! Squarmageddon!
Yes the date of Wednesday 14th June 2017 will live long in the memory of avid square-fillers. I was casually doing my daily VeloViewer refresh when a glance at my “max square” field on the summary had me choking on the contents of my bidon. Having rather smugly expected to see my recently-achieved “50×50” shining back at me, the colour fell from my face at the sight of a mere “20×20”. Surely some mistake??
I frantically switched to the map view on the activities tab, switched on Explorer mode and zoomed in. There it was in red and slightly paler red… my square was a shriveled up ghost of its former self. Dotted amongst the old, lost square dozens of squares were now showing as unvisited. I zoomed right into them and, sure enough, none of the ride lines actually DID go into those squares. But the day before they had shown as visited… so.. had I been there or not? What was going on?
Previously the algorithm for deciding what squares you have been in had to cope with the fact that it was only using summary data from your Strava data. This led to the possibility of squares being visited not being counted (e.g. if a road was a bit bendy, nipped into a square and out again, then the summary straight line might not capture this). Now people don’t like missing out on hard-earned squares, so Ben worked-around the issue by allowing a “buffer” of 100m around the squares. But this mean instead of false negatives (visited squares showing as unvisited) it allowed the possibility of false positives (unvisited squares showing as visited just because you’d been within 100 metres of them).
Now Ben has been able to implement a more accurate algorithm that can truly determine whether a particular ride goes through a particular square (I think by looking at all the Strava data, not just the summary). So there is no need for the buffer anymore. So Ben removed it.
And all us tilers discovered how much we had (almost certainly accidentally) been relying on the buffer to grab us a few squares!
[19th June 2017: Edited to add: The above makes it sounds like Ben forced this change upon the tiling community – this is not true – he did get the express 100% approval before going ahead. Also Ben has now put out his own blog post on the new algorithm – his post is sure to be far more accurate on the details than this one]
All is not lost
It is possible to recover some squares without even leaving the house!
Though the buffer is gone, all your previously uploaded rides still have the squares data associated with them that was generated using the old summary-data-only algorithm. This means you can end up with situations as shown in the image below:
The bottom left square is shown as unvisited, but you can tell from the ride track which road I must have been on, and that road takes me through the bottom left square. Unfortunately the old algorithm didn’t capture this. However help is at hand. Simply double-click on the red line to load the details of that ride. Whilst you reminisce about what a lovely ride that was, behind the scenes the data for that ride is being refreshed to use the new accurate algorithm rather than the old. If we now go back to the map page and force-refresh the page (I used Ctrl+F5 in Chrome), we find the square is now showing as visited:
Of the 2500 squares that previously made up my 50×50 square, 58 of them were showing as unvisited without the buffer. By selectively refreshing a few rides to use the new algorithm, this has come down to 45.
It’s not really the apocalypse is it?
Whilst most of who’ve been building up our max square for many months will surely have some momentary disappointment at it all seemingly disappearing, in truth it is almost the apocalypse – it is a great thing. Here presented to us on a plate is a copper-bottomed excuse to go out and visit more squares. Properly This Time.
As dawn broke the day after the apocalypse, I got right on with doing them Properly This Time. By extending my commute by a mere 10 miles, I was able to pick up a square that I’d never been to before (Strava link ; the new square is the little nubbin close to A3/M25 junction)