Monday, August 27, 2012

A Day in the Field

About 99.9% of the work I do takes place in an office or other indoor space. Occasionally, I get the opportunity to go out in the field for ground truthing. Earlier this summer, I had an opportunity to do this on the lower Columbia River for a project I am doing for the Center for Natural Lands Management (CNLM).

Our ride for the day
In 2009, when the Washington CNLM office was still a part of the Nature Conservancy, I worked on a habitat analysis for the streaked horned lark (as I wrote about on the blog here). The purpose of the current project is to update the analysis with 2011 data and increase the number of sites by a factor of three.

For the original study, I used image segmentation software to classify the vegetation from a combination of scanned and georeferenced photos (black and white, infrared, and some true color) as well as true color NAIP orthophotos. For the current study, I am using 2011 near-IR NAIP with ArcGIS to produce supervised and unsupervised vegetation classifications.

The scale of the dredging/deposition operation is massive
The dredging barge in the channel
I produced draft classifications for three islands and met my CNLM project manager in Cathlamet to get on an Environ boat to tour the islands. Environ is a consultant to the Port of Portland's dredging operations and we were able to tag along with them to gather our field data.

For the ground-truthing I used my Android phone in conjunction with an app called Locus Pro. It worked really well for gathering GPS data with geo-tagged photos so I could take a point and a photo then load it into ArcGIS afterwards (as a KML) to assess the accuracy of the draft classification. It was extremely helpful to be standing on the islands while holding the draft map because I gained a much clearer sense both of the fine differences between classes and also the sometimes surprising differences between what a class looks like on an image and what it looks like on the ground. And we even saw a few larks!

Moss/lichen vegetation

Formerly 'Larky' habitat invaded by Scotch broom

Taking a point

Taking another point (in a very scenic location!)
It was a long day, but extremely productive, and I spent the drive back to Seattle thinking of ways to integrate more field work into my GIS projects!

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