Dialect maps dont necessarily have anything to do with how people live the lives culturally and politically. Seems like a poor option.

I think putting San Diego in a different group than Los Angeles was also rather odd...

Edit: now that I look at it, I would also question their "Urban Corridor" from Los Angeles to Las Vegas... unless they mean people travel between them easily. That corridor is mostly desert.

The data in that first map doesn't match my experience at all. I grew up in Phoenix, and have never met anyone from there who has the pin/pen merger.

That first map, at least, is fairly inaccurate anyway. I've been to central Pennsylvania. They don't speak anything like the people here in southern Missouri. I mean, their speech is recognizable as English, but one couldn't say more than that.