Fieldwork! Day 1

It seems my grand vision of immediately writing up each day's fieldwork experiences immediately after returning to BRASS Base was derailed after our very first working trip to El Pilar. In retrospect, that was probably a pipe dream all along - I'm usually tired coming out of the field on a normal day, and last Thursday (27 April) was a particularly hot one. I've already written about what we did in fairly broad strokes over at Experiment, and I'm trying to avoid overlap between these two platforms as much as possible, so I'll concentrate on some of the peculiarities of our first day in this post.

Bright-eyed, bushy-tailed, and ready to survey in the morning. I wish we looked this chipper at the end of the day.

The day started out like many others last year, albeit with a different set of objectives. Instead of our usual goal of surveying and mapping settlement remains in unexplored areas, we would be checking on a series of problematic structures identified by Anabel's students at UC Santa Barbara. Our project has mapped hundreds of mounds, plazas, platforms, quarries, terraces, chultunob' (storage pits), and other cultural features within the Reserve boundaries, and it's almost inevitable that certain bits of information will get lost in the process. Lucky for us, Anabel has built in a system of data checks that makes resolving these kinds of problems easier.

Today was also a chance for us to test a new extension for ArcGIS - the software I use to make all the fancy maps in here - that would allow us to load GPS points directly into the handheld units without using an intermediary program. This seemed like a good idea that would cut down the number of steps in transferring data and potentially prevent some transcription errors. GPS waypoints help us navigate to features on our LiDAR maps, and we record waypoints when mapping structures to guide their placement in real space. GPS is an integral component of our survey methodology, and we're always looking for more efficient ways to use these data. The results of this particular experiment, alas, were disastrous. The extension would only load 1000 waypoints at a time and returned an error message if you attempted to move to "page 2" of the waypoint list, which doesn't sound too bad, unless you have 1098 waypoints you want to load. Perhaps more ominously, attempts to download any waypoints through the extension crashed the entire program. But we decided to deal with this later.

They look so innocent nestled in their little crate...

An even bigger problem arose from the amount of waypoints we attempted to load into our handheld units, which was entirely my fault. As you can see above, we have four GPS units. They all look the same, but one of them is different. Three are Garmin 62s, and one is a Garmin 64s, which is a newer model with more capacity to handle GPS data. We loaded around 2500 waypoints into these little machines - certainly an excessive number that we would probably never need - but we didn't realize that the 62s models could only handle 2000 waypoints at a time. I checked that the waypoints we needed were loaded (they were) and that each unit had memory to spare (they did - about 3 GB each), but I didn't think to take any test points before heading to El Pilar the next morning. This led to some rather frightening error messages and a frantic scramble to delete unneeded waypoints when we reached the field. Not exactly how you'd want your first day in the field to begin, but we persevered and came up with a contingency plan that worked well enough.

It was not our intention to replicate Dr. Emmett Brown's Flux Capacitor schematic with our GPS tracks

Once we figured out a workaround, we were off to the races. I use that turn of phrase despite knowing of no races through thick tropical undergrowth in 100-degree weather at the time of writing. We estimated our walking distance at between 9 and 10 kilometers, and we covered a pretty good-sized chunk of the El Pilar core area. We did some of this walking on previously cut brechas and trails - whenever we could, in fact - but most of the groups we needed to check were a little off the beaten paths. Here's a look at what we did.

James is standing halfway up the mound.

Now James is on the mound's summit.

Some of the checks were fairly straightforward: locate the problematic mound, record whatever data happened to be missing, and move on to the next target. This wasn't too hard when working with larger mounds, such as the one James is standing on in these photos. If something looked fishy in our GIS drawings, we'd take a quick look around and make a decision before checking that structure off our list.


Other problems were not so easy to deal with, especially when our structure maps didn't accurately represent what we saw on the ground. When this happened, we had to decide what we were actually looking at, quickly measure and re-sketch the feature(s) in question, and take more GPS points to help redraw these features in our GIS back at the lab. Below is an example of what that looks like.

Nothing to see here, just your average mother-and-child mound pair

We thought this map looked very suspicious. You often see mounds of various sizes in close proximity to one another, but a tiny mound abutting a larger one at such an angle could not be taken seriously by any self-respecting Maya archaeologist. We had to see this for ourselves, and decided we were looking at a single, L-shaped mound instead. This could represent two structures that merged together after both had collasped, but there was no way of discerning this from the evidence on the ground, so we re-sketched the map and took more GPS points. As you'll see below, the error in the GPS measurements makes them far from perfect indicators of a structure's outline or position, but they do help guide final map drawing when combined with field sketches.

Getting closer to reality, but it's a good thing we have our sketches

We moved quickly through these assignments and accomplished in one day what we had budgeted for two. But later in the afternoon, as we were walking back out through the bush to the main road and our car, the heat began to take its toll, at least on me. I was mindful to drink lots of water that day, it being my first back in the field doing actual work, but the heat was stifling, and I drank the last drop from my second canteen before leaving our final target. There were no direct trails back to the road, and the trudge through the forest was grim. I began to lose sense of my surroundings in the battle to put one foot in front of the other until we made it out, and I stepped directly over a medium-sized snake - an event of which I would've remained oblivious, had not James and Narcisso, who were behind me, immediately shouted for my attention. This didn't even register until I had taken several steps forward, and at that time I couldn't have cared less. Apparently it was only a boa, but it could've been something far worse. I guess got lucky this time.