Question about distances in UAV vs Airmap

[marcomcarneiro]

Hi folks,
New future drone user here (should arrive within days), so I'm doing my due diligence and learning all I can before flying. I've read laws, blogs and forums, and watched a ton of videos in the last few weeks, and there's one thing that I can't seem to understand.

I have read here and in other forums, that I can use the UAV site (UAV Site Selection Tool) to see where I can legally fly in Canada. I have also learned about the Airmap tool/app, which seems to be even better in its capabilities.

However, when looking at my region, I noticed something:

Notice how some of the circumference vary in size?

Then I picked one random circle and measured (by eye, so very approximately) it's radius on Google maps.
UAV:
-
Airmap:
-

So it seems that the UAV site is using about 9km (maybe 5.6 miles?), while AirMap uses about 5.4km, which is what is on the TC rules.

Can anyone verify if you've been through this? Airmap seems to be closer to the rules, but UAV at least sounds more official, and Canadian.

Thanks in advance!
/Marco