After reading the legend, I think there are some regional differences that just aren't captured. The notation is extremely specific to certain sounds.

Looking at this, one would expect that a western Canadian wouldn't be able to know if someone was from Toronto or not.

This is obviously wrong because they pronounce "Hello" as "I'm from Toronto" and that is an immediate clue that they're from Eastern Canada. (JK jk)

But seriously, Torontonians hit the "ars" (it's not far to take the car to the bar) to a western ear like a fucking pirate. Yar Har Har.

It's obviously more prounced and comes with much more colourful additional pronunciations as you get into the Atlantic provinces, but the pirate ars are still solidly in Toronto.

I don't see in the legend a "pirate ar" notation.

Well, hard to tell. The print doesn't show well while zoomed in for me. Best I can say is that from what I can see, it isn't too horribly off from my local ares.

Edit: found a section of the site that zoomed better.

Nah, they entirely missed the Appalachian dialect. It's pretty distinct from what they're calling inland south, enough so that it's recognized as its own thing.

Only part of that is about pronunciation, there's usages and unique words too. Which makes this map all si-gogglin.

From Georgia, this is not nearly detailed enough to cover the south

I grew up in Denver, my fiance in Arkansas

Pin=pen, pin≠pen will absolutely be the cause of our divorce.

What the fuck, I have a accent?