"left" and "right" sides of glacier boundaries

[Roger Barry]

Bruce:
I fully agree with Georg and was going to send you that convention,
Roger


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  Dr. Roger G. Barry
  Distinguished Professor of Geography and
  Director, National Snow and Ice Data Center (NSIDC) and
  World Data Center (WDC) for Glaciology, Boulder

  CIRES/NSIDC
  University of Colorado              Phone:  (303) 492-5488
  UCB 449                             FAX:    (303) 492-2468
  Boulder, CO 80309                   E-mail:  rbarry at kryos.colorado.edu
                                               http://nsidc.org
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On Fri, 25 Feb 2005, Georg Kaser wrote:

> Dear Bruce,
>
> I would propose that a decission is not led by the demands of a certain
> method but should follow the convention that left and right in sciences
> related to the earth surface is defined as orograpically left and right.
> Look into the direction water (ice) flows and assign (the glacier
> boundaries) to either left and right. I would stick on this even if it
> makes the application of a given method more complicated.
>
> Best wishes, Georg
>
> Georg Kaser
> -------------------------------------------------
> Institut fuer Geographie
> Innrain 52
> A-6020 INNSBRUCK
> Tel: ++43 512 507 5407
> Fax: ++43 512 507 2895
> http://meteo9.uibk.ac.at/IceClim/CRYO/cryo_a.html
>
> On Thu, 24 Feb 2005, Bruce Raup wrote:
>
> > Hi all,
> >
> > As you probably know, the GLIMS database provides for storing information
> > about what materials and features are on the left and right sides of
> > glacier boundary segments, and the GLIMSView program makes it fairly easy
> > to assign such attributes to digitized glacier boundaries.  However, the
> > definition of "left" and "right" hasn't really been firmly specified.
> >
> > Ultimately, it would be nice if in GLIMSView, you could just click on one
> > side or the other and not worry about whether it is "left" or "right".
> > But we're not there yet.
> >
> > I propose the following solution.  Since it might negatively impact those
> > who have already assigned such attributes, I want to get your feedback.  I
> > propose ordering all polygons to be in counter-clockwise order (interior
> > on left) at ingest time.  References to left and right would be according
> > to this vertex ordering.
> >
> > GLIMSView currently outputs polygon segments with points ordered in the
> > direction of digitization, and can therefore output segments with
> > inconsistent direction when placed within the polygon.  My ingest software
> > already puts the segments together so that they match up end-to-end in a
> > consistent direction.  Now I'd like to make the handedness consistent too.
> >
> > Comments?
> >
> > Bruce
> >
> > --
> > Bruce Raup                                               Phone:  303-492-8814
> > National Snow and Ice Data Center, U. of Colorado, 449 UCB, Boulder, CO 80309
> > http://cires.colorado.edu/~braup/
> >
>