Take the 2-minute tour ×  Is it possible to return the boundary
(outside) permiter of a polygon layer?  Let's say you have the
map of the USA, for simplicity, broken down to the county level,
is it possible to return the boundary map of the whole country
from that map?  share|improve this question So in the example
case of the US, you mean actually get the outline of the states,
NOT the bounding box, right? If so, how about a dissolve of the
counties layer? –  Chad Cooper Nov 19 '10 at 18:47 @Chad Cooper
- when I dissolve the layer, i still get some lines showing up
for counties and states. –  dassouki Nov 19 '10 at 20:18  7
Answers 7  up vote 5 down vote accepted  You can just do a
dissolve on the county layer (be sure to have just the counties
you want to dissolve selected).  share|improve this answer I'm
getting some internal lines still showing up in dissolve. – 
dassouki Nov 19 '10 at 20:13 Can you buffer twice to eliminate
the internal lines? Out, to "eat" the lines, then back in, to
restore the origina