Working with arcGIS in the BlueRidge: Week Three of Summer Research


Today marks the third consecutive week of my summer research focused on uncovering the past history of the Appalachian mountain range. The first week of the summer was spent examining the current literature. I focused on reading articles related to my research methods of stream profile analysis (e.g Gallen et al. 2011) and cosmogenic radionuclide dating (Bierman et al. 1996). Reading through these helped prepare me for lively discussions with my research team: my advisor Greg Hancock and research partner Tiff Choi.

The second week of research involved getting acquainted with ArcGIS software. Somewhat familiar with the program from my Intro GIS course last semester, I immediately tried to integrate my research goals with the various GIS tools at my disposal. One of the perks of working with ArcGIS is that it has a relatively refined model builder feature. This allows some level of automation as a string of different tools can be combined and run with different inputs. One example of a model I made is one that extracts watershed hypsometry from a digital elevation map of my study area. Hypsometry is a plot of elevation versus area. They are a useful tool in examining landscapes because they can help visualize (in graph format) where the majority of the elevation in a watershed is located. The changes in area vs. elevation with increasing elevation also reveal the changes that a landscape has undergone. For instance a shallow line with a sudden increase in area is often associated with migratory knickpoints.

The goal for the current week (week three) is to finish graphing the majority of hypsometry and slope plots of tributaries within the two major watersheds in my study area (the Tye and Irish Creek watersheds). Once completing this, Tiff, Greg and I can collaborate to determine where we should sample in the field during week four. Our sampling is meant to pinpoint relevant tributaries for determining basin average erosion rates. Hopefully at the end of next week, I will have some preliminary field research to report on.

For brevity, I have not elaborated on some of the research concepts that I have referenced. If anyone is interested further, I would be happy to respond to a comment or take up email correspondence. Thank you for reading!


  1. svcollins says:

    Hi Nathaniel! A lot of your research is somewhat over my head, as I have no experience with GIS. The Appalachians are dear to my heart though, so I think it’s really cool that people at W&M are researching them! Quick question about your work: are you looking for natural erosion, manmade erosion, or both?

  2. ermclenigan says:

    Hi Nathaniel! I have a clarification question. You mention migratory knickpoints – do these refer to elevation drops that are moving due to erosion (e.g. from waterfalls)? And can you explain how/why exactly a shallow line with a sudden increase in area represents that? I’m not sure I’m understanding the visual. Thanks!