ArcMap-based script available for finding ice divides
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@nsidc.org
Hi Bruce, I wouldn't mind getting a copy of the script to compare with our own. Cheers, Luke. -- Dr. Luke Copland Department of Earth & Atmospheric Sciences University of Alberta Edmonton, Alberta T6G 2E3, Canada Tel: 780 707 5583, Fax: 780 492 7598 luke.copland@ualberta.ca
Dear all As decided during the GLIMS workshop in Chamonix in September, the algorithm working group is planning to set up a GLIMS algorithm document. The aim of this document is to collect descriptions of any algorithms useful for GLIMS. Please find under http://www.geo.unizh.ch/~kaeaeb/glims/algor.html a first draft of the document outline, to a large extent based on Frank Paul's work. The draft is by far not complete and I will continue with it. Please provide short descriptions on algorithms (similar to the one already on the www-page) you don't find in the document, or with any other suggestions, changes, literatur, links etc. You will be included on the author list of the document :-) The next steps of the algorithm working group will be: 1. Completion of the algorithm document draft 2. Decision on the most promising algorithms for glacier mapping within GLIMS 3. Comparison of these algorithms using case studies 4. Selection of a small number of GLIMS glacier mapping algorithms 5. Implementation in glimsview (a tool available for every GLIMS co-worker). Feel free to forward this e-mail to any other GLIMS collaborator potentially interested. Hope to hear from you! Best wishes Andy Kaeaeb
Andy, That's a good start. For the section on IMCORR, perhaps you could simply link to http://nsidc.org/data/velmap/imcorr.html Also, for use of a DEM in delineation of glacier boundaries, I can (eventually) provide a description of the prototype I developed using seed points and DEM surface curvature. Michael Bishop has much on this also. BTW, for the merits/demerits of something, in English we generally say "pros" and "cons". Cheers, 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@nsidc.org
participants (3)
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Andreas Kaeaeb -
Bruce Raup -
Luke Copland