The "gerry index"
gives a measure of how gerrymandered different districts are.
(we mathematicians call this the "isoperimetric ratio").
The index is always at least 1. For a circle it is 1.
For a highly gerrymandered shape, it is large; they claim 2 to 2.5 is
"suspect" and above 2.5 is definitely gerrymandered.
You can click on a gizmo to find out the gerry index
and get a map of any US congressional district.
Unfortunately I am somewhat suspicious of their numbers because
for many shapes such as coastlines, the more finely you measure it, the longer
the boundary curve gets. A coastline has tiny wiggles
which you see when measuring with a 1-meter-long ruler, but
not when measuring with a mile-long-rod. I believe that many
of the worst congressional districts would also have that "fractal"