GIS for Fun: My Digitized BBS Route

The North American Breeding Bird Survey (BBS) was meant to be a stratified random sample of the continent’s terrestrial bird populations, so we could monitor the pulse of populations and trends. When I went to the American Ornithologists’ U/COS conference (back when it was still called that) in 2015, I presented in a symposium dedicated to BBS. The opening talk was about the history of BBS, which helped give me some historical context about the data set. It added a dimension to my understanding of the time periods of ecological research. The data set was developed before landscape ecology really took hold in the U.S., and along with it an explicit awareness of spatial analysis.

The spatial data we have for the BBS is what I believe to be digitized route paths from old highlighted paper route maps. As such, it’s rife with errors: I’ve found routes in the layer of many variable lengths, but some egregiously too long. Being that it’s a volunteer effort, it’s at times hard to get clarification on what’s going on here. I’ve done and continue to do analyses based on these route paths, so their accuracy matters to me. Side note: if the United States Geological Survey – Patuxent would have me, I’d be happy to travel the country in something like the “Google street view car” and help digitize these routes during BBS season! Just putting that out there.

I decided to pull up my route in GIS to see what calculated stops would look like, by first placing stops every 0.5 mi. (probably the more correct method) and then placing 50 equally spaced stops along the route. Since the route is a little long, the 50 stops end up probably being more spread out than they should be. Also, as route runners know, it’s not an exact science, in that you might need to move a stop up to 0.1 mi. for safety concerns.

Anyway, when I synced this up to road data, I found that the routes were significantly off from the latest road path data, probably because the latest version is > 4 years old now. The road data I’m using is quite intensive, and I’m trying to figure out what to do next. How will I line up the paths, and will this little experiment even matter in the long run?

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