Group E Data: Week 9 (Measurement)


Data from Lab Group E from May 25, 2023.

Group Members: Luisa, Marta, Jake, Dylan

This week, our lab was once again dominated by qualitative data that came from our experiences working with our group’s Groma. Our group completed three tasks: outlining two templa (one 7x7m, the other 14x14m), building a “road” across part of campus, and centuriating part of the “Midi” Bald Spot with members of other groups (located on the campus of Carleton College). In terms of general procedure, we used the Groma’s three hanging strings to align poles (held by group members) at a distance with our zero point (defined by the middle string of the Groma). Points were marked with colored flags after linearity had been determined. Our group’s findings for each task are discussed below.

Templum (Square)

Attempt #1: We found our initial attempts to create a simple square/templum to be fairly challenging. For starters, we struggled to implement any real procedure to measure out the lengths of each side, as it took three to four uses of the measuring wheel with subsequent pole alignment to get our initial sides at the desired length of 7 meters. However, when we went to check our measurements, we found that one side of our grid measured 8 meters instead of the desired 7, indicating that our angles hadn’t been kept at 90 degrees. Despite our attempts to correct this error, we were never quite able to get the sides equidistant – the closest we got was the final side measuring ~7.5 meters.

Despite this failure in outcome, our first attempt taught us some valuable lessons about the Groma-surveying process. First, it became abundantly clear that two people were needed to operate the Groma in order to keep a straight line over the correct zero point – one person’s role would be to hold the Groma steady over the zero point, the other to line up the poles with the Groma’s strings by directing the people holding the poles to the right spot. In making right angles, the matter of keeping the zero point constant (as well as maintaining the angle of the Groma’s “axes,” for lack of a better term) was extremely important, so the roles of both the Groma-holder and the person responsible for alignment were equally important. Additionally, although we first attempted to keep our central string in-line with the other two strings on the Groma by taping it in place, we discovered that aligning the two end-strings (front-back) with the pole was more efficient and produced the same outcome as when we had attempted to get all three in line with the pole. Perhaps a Groma with a more accurate string alignment would not have this problem; however, our Groma’s center string was used for little more than determining the zero point after the first attempt at the templum.

Attempt #2: Our second attempt at marking out a larger templum (14x14m) went much more smoothly. Having learned much from our first attempt, we went into our second trial with a clear process:

  1. Measuring the approximate desired distance with the measuring wheel from the zero point
  2. Align the pole with the Groma’s strings
  3. Re-measure the distance and re-align as necessary.

This method proved to be much more effective and time-efficient, as we achieved an almost-perfect 14x14m grid without having to correct our initial measurements. As a team, we worked much more smoothly during the second attempt, as each person had tried every role during the first attempt and had a good sense of what was needed.


Before we began building our road, we elongated our Groma’s center-string to make our zero point easier to determine. Since we had to move the Groma quite frequently throughout the road-building process, this decision proved incredibly valuable to improving the speed with which we could determine our new zero point.

In terms of our process, we would measure 2-3 poles from each zero point. In all, our road consisted of three continuous straight portions with two turns at various obstacles. After roughly 40 minutes, our “road” measured ~520 feet in total, spanning from the southeast side of the Mini Bald Spot to the northeast corner of Myers dorm.

Approximate visualization of our “road”

The road-building process proved to be far less intense and mentally taxing than laying out the templum. Since our group did not measure out equal distances between road markers, the relative ease of road-building probably came from having a far simpler/easier process. Additionally, the change of scenery that road-building provided was very welcome and somewhat relaxing after spending the better part of an hour creating our two templa in a fixed location. Below is a timelapse of the distance we covered with our road.


Our group numbers dwindled slightly as we attempted to centuriate part of the “Midi” Bald Spot, going from four to two in the span of 15 minutes. This proved fairly problematic, as we soon discovered that three people are the minimum amount needed to reliably operate the Groma – at our skill level, at least. However, once we found some substitutes, we set about dividing a portion of grass into four 30×32-foot rectangles.

Working together with another group (one group starting in one corner of the larger area, the other starting parallel from the first group in another corner), the most important and time-consuming element of centuriating was making sure our starting corners were aligned with one another. Once we had set the two Gromas 64-feet apart from one another and determined our 90 degree angles were correct, we lined up one pole at a distance greater than 60 feet away with our Groma’s strings. We then drew a string tight from our zero-point to the pole and marked out two 30-foot increments along the line – these were directly across from the other group’s 30-foot markers. To finish the process of centuriating, we finally connected our new markers to those of the other group with a string and measured out distances of 32 feet (halfway between the two markers). The use of the string made the process of centuriating far easier than that of laying out the templa, as it felt like something in-between road-building and laying out a simple square in terms of attention/focus required.

Our centuriated grid of four 30×32 foot rectangles (marked by neon green flags)

Concluding Thoughts

Communication: Good communication skills and good relationships between team members were just as important as Groma-operating skills during this lab. Because so much of the lab’s communication was directive in nature (telling someone to move a certain direction or for clarification about instructions), surveying has the potential to be extremely frustrating at times. Clarity, concision, and remaining considerate of one another were all key parts of maintaining good communication and good group morale throughout the lab.

Appreciation of the natural world: Luisa made a remark while we were laying out the road that this kind of work really furthered her connection to the landscape and the world around her more generally. This sentiment rang true to me as well, particularly during road-building (a task that required less intense focus than either templum-measuring or centuriating). Once we got “in the groove” as a group, there were several moments when I also felt as if I had a much better appreciation for the campus’s natural beauty.

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