ArcMap-based script available for finding ice divides

[Bruce Raup]

Hello all,

Bill Manley, a research associate at INSTAAR (Institute of Arctic and
Alpine Research, Univ. of Colorado), has created an ArcInfo-based script
to break polygons delineating large ice masses into separate "glaciers",
based on ice divides. Inputs to the routine are

  - ice polygons
  - coregistered DEM

The script

  - fills small holes (sinks) in the DEM
  - creates a flow direction grid
  - finds glacier "toes"  (grid cells below the median ice mass elevation,
    to be used as "pour points")
  - uses the "watershed" command to produce a grid where cell values are
    basin numbers
  - combines the basin grid with the original ice polygons to create
    separated glacier polygons

I have seen the output of this algorithm, and it seems to work quite well.

Bill has generously decided to make this script available to the GLIMS
community if there is interest.  If you are interested in obtaining this
script, please let me know.

Bruce

-- 
Bruce Raup
National Snow and Ice Data Center                     Phone:  303-492-8814
University of Colorado, 449 UCB                       Fax:    303-492-2468
Boulder, CO  80309-0449                                    braup at nsidc.org