Monday, May 10, 2010

Finishing up True Area Analysis

I have finished my true area analysis for each glacier on Hood and Rainier for the low snow years 1987, 1992, and 2005. I was able to use outlines from Andrew Fountain for most of the glaciers on Hood and I used the GLIMS outlines for the ones that I didn’t receive from him (ZigZag, Palmer, Glisan, etc). I didn’t need to digitize any outlines myself but I did modify some of the GLIMS outlines to better fit the hillshade and glacier shapes which I noted. I thus have measurements for area change on each of the 11 major glaciers on Hood. I also have measurements of true area change for all 28 glaciers on Rainier as well as some measurements for changes in size of the Muir Snow Field.

I took the time to convert files for ease of use in Arc Glob which will allow for 3D viewing of the coverages laid on top of the hillshade with the bare earth LiDAR DEM as the elevation source. The images on the right show the work. I’ve used the same coloring scheme for both mountains for the earlier year outline (1972 for Hood and 1913 for Rainier) and for the later year outline (1984 for hood and 1994 for Rainier). The later year outline is represented in the images on the right. I can change these colors but it would require changing the display properties of several hundred files representing the glaciers over various years.

Now that I have the true area measurements my next step is to create some figures in excel from the data showing which glaciers seem to be retreating the fastest and perhaps look at how the slope of glaciers relates to their speed of retreat as well. I also need to make a comparison of how using the two different outlines for each stratovolcano effected the results. I think the better outline for Hood was 1972 but the better outline for Rainier was 1994 - just by looking at my results. On wednesday I need to finish up converting the files for Arc Globe 3D for Hood but that shouldn’t take too long.

My goal by the end of the week is to sketch out an outline for you of my writeup as well as I really need to get started on the writeup. I’m going to head over to the Graduate School to get a list of grad reps because I still need one and I’m going to ask Dawn to video conference in for my defense as I feel most comfortable having her on my committee rather than someone I’ve not had any interactions with. She can help me in the final stages with my GIS work as well.

Things are coming along well now and I can almost see the light at the end of the tunnel. The one HUGE puzzle piece in this that is still missing is the locations of debris flows on Mt. Hood. What do you suggest?

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