# Calculate the shortest distance across a polygon.

Discussion created by roryhall on Nov 4, 2010
Latest reply on Nov 5, 2010 by csny490
Hi all,
I appologise in advance here as I am flying a bit blind.
I am trying to find a method to calculate the shortest distance across a polygon. My line of thought is to get access to the points that make up the segments between vertices and shoot out a line perpendicular until it reaches the opposite side of the polygon measure that line and find the shortest.
What I need to know is how Arc manages the geometry for polygons and how to get access to that for the calcs. I am assuming the topology is managed using something like a polygons can is either be on the right or left side of a shared line. How do I access this data and the points data?
There are two outcomes I hope to acheive here is, can someone point me to to a "doc" describing how Arc manages polygons especially topology, and to actually acheive the task.
This is one of those "Are you able to do....." requests, and I am sure you can but don't really know where to start.

Thanks in advance for anyone help
Cheers ~ Rory