region borders misplot for concave regions

[pabloitu]

The boundaries of a region fails to plot correctly when the region is concave in the x axis (a horizontal line touches the region twice).
See northern edge of NZ, or two small cells in the eastern edge:

will try a quick solution using shapely (merge cell polys and then get boundary)

[wsavran]

Good catch! Do you have any idea why this is happening or better yet, any ideas for a fix?

[pabloitu]

I would try to use shapely (pygeos) to find a quick boundary extraction instead of coding it myself. Will take a look at it