The article is kind of confusing, because the event itself was kind of complicated.
There were multiple events that day, including a marathon and two separate half-marathons (neither of which was actually the same as the marathon course). The actual marathon was measured correctly, as was the other half-marathon.
The other half marathon was measured correctly, but they then sent runners down the wrong course.
The actual measurement process is extremely well defined by the certifying body. But after that it's up to the event organizers to draw up the map (which is where the error was made) and put up signs (which they did correctly, following the incorrect map).
Haha, reminds me when I got myself a trial membership at the cheapest gym in town. When I hopped on the threadmill, it consistently reported that my speed is on par with Kipchoge's 2 hour marathon run, without me even breaking a sweat. Though I really felt flattered, it felt a bit off.
There were multiple events that day, including a marathon and two separate half-marathons (neither of which was actually the same as the marathon course). The actual marathon was measured correctly, as was the other half-marathon.
The other half marathon was measured correctly, but they then sent runners down the wrong course.
The actual measurement process is extremely well defined by the certifying body. But after that it's up to the event organizers to draw up the map (which is where the error was made) and put up signs (which they did correctly, following the incorrect map).