-------- Original Message --------
Subject:        Re: "Natural borders"
Date:   Thu, 3 Nov 2011 13:34:23 -0700
From:   Dyallen2 <[log in to unmask]>
To:     Maps, Air Photo, GIS Forum - Map Librarianship
<[log in to unmask]>



It should be pointed out that historically and philosophically "natural
borders" is an extremely dubious concept. Borders between states are
always devised by people and do not exist in nature. Is the Rhine River
the "natural border" of France? At various times France has claimed that
river as its natural border, but neighboring states like Germany have
disagreed, to put it mildly. Is a small tributary or a range of hills a
natural border? Efforts were made in the nineteenth century to establish
the border between Maine and Canada using such features, but there was
at best little agreement on what might constitute natural borders in
this area. These problems and inconsistencies could be multiplied many
times over. Under these circumstances, it is simplistic to think that
all of the natural borders in the world could be mapped using GIS or any
other technique.
David Allen
Stony Brook University (retired and cranky)
In a message dated 11/03/11 10:59:22 Pacific Daylight Time,
[log in to unmask] writes:

     -------- Original Message --------
     Subject: Re: "Natural borders"
     Date: Thu, 3 Nov 2011 17:41:22 GMT
     From: [log in to unmask] <[log in to unmask]>
     To: [log in to unmask]
     CC: [log in to unmask]


     My sense of it is that it would still be fairly labor-intensive even
     with GIS. I attempted a similar project with U.S. Counties and had
     limited confidence in my result. You could possibly use segment length
     as a heuristic -- short segments might indicate a natural border while
     longer ones might indicate an arbitrary? artificial? man-made?
     straight-line? border. (I don't like any of those terms). However
     there would still be chance of a mistake. A border might be straight
     for a while and then have an unexplained notch - the notch might be
     something natural like a ridge, or semi-natural like a canal, but it
     might just be a property fence. Long segments might indicate merely
     sloppy digitizing rather than a true straight-line boundary.

     Is the patron wanting a percent value or something? A jagged stream is
     going to contribute more length than a straight-line boundary. Or is
     each link (say Jordan-Iraq, Jordan-Israel, etc.) to be equally
     weighted,
     with mixed boundaries getting appropriate values?

     Joe McCollum
     Forest Inventory and Analysis