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Reply To: | Maps, Air Photo, GIS Forum - Map Librarianship |
Date: | Thu, 3 Nov 2011 12:57:51 -0500 |
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-------- Original Message --------
Subject: Re: "Natural borders"
Date: Thu, 3 Nov 2011 17:41:22 GMT
From: [log in to unmask] <[log in to unmask]>
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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
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