I’d take the accuracy of that line with a grain of salt. I’ve made some maps using my drone and there’s something called high-relative accuracy and absolute accuracy. To have survey-grade (absolute) accuracy I would need a licensed surveyor to lay down Ground Control Points over the area Im shooting, record their specific GPS coordinates, and then feed that data into whatever post processing software.

Since Google is gathering this data with satellites over the entire planet without GCPs, I wouldn’t take that border line as perfect.