I work a lot with lot an usually apply region union to find the perimeter, but for this specific case it does not seem to work at all. It doesn’t show in the screenshot, but the result is empty.
If have already double checked the lots are not repeated and that all of them share a vertex points.
I’m sorry… I really believed I already had uploaded the file. But I don’t know why I deleted the geometry and Ctrl-z and it worked. Thanks for the help though!