Friday, September 5, 2008
Geo-Rant: My Quads are killing me (and wasting tons of time)!!
No, not because I spend so much time hiking in the desert or because I lugged way too much crap down the South Kaibab Trail last month...not those quads. What is killing me is being a victim of mapping 7.5 minute quads. Mapping 7.5 minute quads is a waste of time. It is efficient only in a clerical sense, not in a scientific sense. Mapping on the basis of 7.5 minute quads amounts to mapping in a rectangular frame with boundaries that are (aside from some amazing coincidence) completely arbitrary with respect to geology.
Obviously, the implied goal of mapping 7.5 minute quads is to allow for a systematic framework for eventually mapping a bunch of officially circumscribed rectangles that cover an entire state or region. The key words here are 'officially', eventually', and 'rectangular'. Morevover, the concept of mapping quads is so deeply mired in the deeply pre-digital history of the USGS and the history of printing that it has become an ultra-anachronism.
I have been foolish enough to map a patchwork series of quadrangles along the lower Colorado River in an attempt to better understand the river's geologic history. Each time I move into a new quad, I learn more about that history (or more variations on it) that inform previous maps. Why in the hell I didn't just try to get funding to map the deposits of interest along the corresponding length of river is beyond me. Eight years later, I am still trying to finish some of those maps (sure, I am a perfectionist, but there are other reasons).
My most ambitious mapping project, the Ivanpah Mega-Map (Ivanpaviathan), is a classic example of how mapping quads can (temporarily) wreck your life. In that case, I stupidly proposed to map the entirety of all of the quads that fell even partly into the boundary of the watershed of interest. WTF? What an idiot. That is how mired I was in the Quad Mapping Model (QMM). I paid and paid dearly for that bit of stupidity.
My job involves mapping a lot of quads in Nevada. My agency has a goal of eventually mapping the entire state. Ha! That is not going to happen at 1:24,000 in my or my kids' (or their kids') lifetimes. In fact, this is simply not going to happen ever! Deal with it. Pick the areas that really matter (for whatever reason you like) and map them. Don't worry, you can still circumscribe the area with a quadrilateral that has easily defineable corner coordinates....
Posted by Dr. Jerque at 2:00 PM