Field School Week 2: Mapping and Context
Students learn mapping as their first major field research skill. We begin with mapping because this is the first skill from which all other archaeological tools derive: the ability to know where something is in relation to other things. An archaeologist must be able to control their data collection, locating things in space and time on the landscape. You can think of this in one way as the X, Y, and Z coordinates where a thing was found. We call that information an artifacts provenience, and because we know how things relate to each other in space (and thus time), we can say things like “These two artifacts were buried at the same time, roughly 1855″ or “That button was manufactured in 1863 and it was in a layer of sediment deposited when this foundation was laid, so this building was built sometime in or after that year.” If someone brings me a button or bottle that they have removed from a site, they have lost most of this information and that greatly reduces the information we can learn about daily life at the site through that object.
So knowing where things are is key. Building from that, an archaeologist needs to be able to put things they see on or in the ground into the absolute space of maps, using systems like UTM, Township and Range, or Latitude and Longitude. These skills matter because it takes a great deal of work to be able to look at a foundation on the ground today and definitively say, this is the foundation of this structure indicated on this 1849 map. Figuring that out can be very hard. Just ask Sean and the other research team members.
The students eventually learn to work with an EDM/Total Station, GPS, and sometimes other technologies like LiDAR. When we teach mapping, however, we really start with basics because we want the students to understand the processes behind the button pushing for digital data. The students start learning basics: the significance of triangles and trigonometry; triangulation by measurements, triangulation by bearing, and bearing-and-distance mapping; determining scales; and drawing by hand.
We spent time during the first and second weeks making maps of campus buildings. One team stretched tape measures to build a triangle of three base points, then measured distances from those points to all the key building corners. The second team used magnetic compasses to take bearing readings off magnetic north from a single point, then measure the distance. Then both teams plotted their buildings onto hand-drawn maps at the same scale. This was the result:
Not bad for a first try!
This is an optical transit, similar to the model used by Michigan Tech Industrial Archaeology students when they learn the basics of surveying and map making. Creative Commons image courtesy of Land Surveying Services, Inc.
Later, when we went into the field to the South Cliff Stamp Mill, we pulled tape measures to lay in base points and started making our map of the building remains. We also started learning how to use an optical transit. This is pretty easy to learn until you depress or incline the angle of your telescope, so I’ll spare you all the math. Using the optical equipment certainly prepared the students to appreciate the EDM and GPS units!
This schematic diagram shows computations of distance using stadia measures, when the transit is level. Creative Commons image courtesy of the Food and Agriculture Organization of the United Nations.
Kaeleigh, Jordan, Rob, and Connor plot points on a scaled map of the South Cliff Stamp Mill. And yes, that is snow on the ground at the end of May in the Keweenaw.
Tim Goddard teaching Connor Will how to use the Total Station/EDM to collect geospatial data.
As the work progressed, the students generated a scaled drawing of the mill’s main features in the field. Working from this drawing, they were able to then select areas for shovel test pits. We wanted to assess the potential of the South Cliff Stamp Mill for archaeological excavation.
The third week, Tim Goddard was able to spend some time with us in the field, teaching about the EDM/Total Station as a tool for collecting geospatial data. The students learned quickly and they reshot many of the South Cliff points again, so we will be able to compare the digital with our “analog” data. The EDM data will allow us to easily add the new information about the South Cliff Stamp Mill into the CliffMAP GIS.
Kaeleigh Herstad levels the prism to record machine anchor bolts in the South Cliff Stamp Mill.
We were generally pleased with the results and look forward to showing our open house visitors the stamp mill site and explaining what we have learned about it during the week we spent studying it. We’ve only had a quick and preliminary view, but it looks very promising for more research. This mill also has an interesting story as a place of technological experimentation and it gave us tantalizing clues!
Student Blog #4: David Kroos
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Hey readers, my name is David Kroos and I’m a 4th year Computer Science major with a Historical Studies minor. I thought field school would be a fun way to finish up that minor while covering my general elective requirements. So far, I haven’t been disappointed. Working all day in the field has been surprisingly nice […]
Field Work Begins
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Sorry about the delay in posts. I am currently finishing up some writing on another project so I was away from Cliff-related work for a few days. Yesterday, we finally got started on field work. One of our grad students, Roger (a returnee from last year) is working on a thesis project centered on the […]
Day 2: Learning to Map with a Compass
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Today was mostly spent on campus learning about and practicing the art of making a map. First a quiz was given, and although the scores were pretty good we still need some work getting the basics of early Cliff and Keweenaw history down. Luckily we have a few weeks to prepare for public tours. After […]
Student blog entry: Roger’s experience
From time to time I will be sharing with you the experiences of some of our students. this first student entry of the season is from Roger, an incoming graduate student to the Industrial Archaeology program who brings a lot of field experience to the Cliff Mine archaeology Project.
My name is Roger. I am a new Graduate Student at Michigan Tech University. I received my B.S. in Anthropology from the University of Oregon in 2005. During my time there, I worked on the Southern California Channel Islands Project. I did cartography, lab work and was a computer technical advisor for this project. I studied at New Mexico State University’s Anthropology graduate program. While there, I worked on the Lunar Legacy project. The main focus of this work was preservation of Human Artifacts on the Moon and the Natural Effects that can negatively damage Lunar Archaeological sites. I have given three papers on this subject at three different conferences and co-authored a chapter in the text book, “Handbook of Space Engineering, Archaeology, and Heritage.” I participated at the Rough ‘n Ready Field School, excavating an 19th century stagecoach station. Recently I have been working for the Inyo National Forest for the National Forest Service. I am a co-author on National Register of Historic Places nomination on the Lon Cheney Cabin of the High Sierra.
I have been working at the Cliff Mine Field School. This is my first Industrial Archaeology dig, so I have been excited about it. I have been spending most of my time working with one of our instructors (Tim Goddard) on the cartographic mapping of the site. I have had a little experience in working with the Total Station, so I was chosen to be Tim’s assistant in working the station. Mostly I have been holding the prism for the laser site while Tim shows the other students how to set up and shoot points for mapping purposes. Incidentally if you see nails with flagging tape around it, please do not pull them out. It took a great deal of time and effort to lay those out in tick infested swamps and poor rock piles and it would be a serious blow to our schedule to put them back if they were removed.
Today, a fellow student and I opened up a new unit, SM101.t6. This unit is the first of its type for me to dig as it’s half in an exit for stream run-off. Half of the time we are excavating and the other half ditch digging. Draining this trench unit is a time consuming effort that has been a real, but necessary, pain. Tomorrow I am considering bringing a pump and a length of pipe. Then I can pump and bottle the water to sell it as an all-natural mineral water. I could call it “Old Cliff: the all-natural mine water that tastes like 1850.” Anyway, our unit has some interesting details and soils that has made it enjoyable. So far this has been a good experience, but soon I think I will be returning back to Tick Hollow Clifton to map areas of the townsite. So until next time, Adieu.
Week 1: Part 2
Field School instructor Tim Goddard (center) teaching total station surveying to some of the field school students.
On Wednesday, the students got their first taste of what its like to work in a heavily forested (and trampled) archaeological site. The students were divided into two teams: one to learn the basics of digital mapping, the other to measure and lay out our excavation areas. Today’s post will cover the progress of the first team.
Last year our field teams spent the majority of our time digitally mapping the Cliff Mine site, focusing on the industrial remains located at the base and atop the bluff that gives the mine its name. In order to do this, you use what is called a Total Station, a surveying instrument that stores distance measurement information that can be integrated with software on a computer for storage and display. It is a common site to see road crews and civil engineers using these tools to accurately site property lines and construction boundaries. We use it for very similar purposes.
The first thing you need for accurate Total Station mapping is good, consistent, ground control points from which to establish yourself when you begin your survey. Often, known survey pins (with known GPS coordinates) embedded on the sides of roads or as corner markers are available for this. In our case, last year we were able to find two of these points that we could then begin our entire project off of. From these two points we were able to accurately sitein a few dozen more control points around the site, and eventually from these control points, shot in another 4,000 plus points corresponding to artifacts, walls, and roads.
One of the maps created from last year's mapping survey.
This year, we needed to re-establish those early controls in order to make sure this year’s mapping is consistent/accurate to last year’s. Unfortunately, the weather and maybe even some curiosity made for a difficult time in that re-establishment. Both of our original points were removed, one intentionally, one by the forces of nature. Many of our other control points were also removed by the same two processes over the site. Metal detectors pick up on the nail (the control point), and then people pull them up.* Simply walking around the site disturbs the nails as well, and even a few centimeters difference in their placement from one year to the next can mean an accuracy change of several meters given the size of range of elevation at Cliff.
The students were therefore tasked with creating a new grid of points off of last year’s field notes from which to build this year’s mapping. After two days of walking the site and trying to find multiple older points outlined in the field notes that were connected by line of sight, they were able to do this. It took a bit longer than expected, but allowed the team members to learn a valuable lesson, that site integrity is not easy. It is always important to have a back-up plan and accurate recording of your work so that future researchers can follow your lead and not have to start from scratch every year.
*To those of you who do metal detect at the site, I am not complaining about your practices. I may disagree with some of your methods and feel that the site’s artifacts should be left for study, not for sale or for a box in the attic, but I know that people have the right to the public lands too. And I know that many of you have valuable information I’m dying to hear about.
If you are going to metal detect or walk the site, please leave any nails or artifacts flagged with bright tape in place. These are not marking important finds, they are marking our control points we need to continue our work.
Some Videos of the LiDAR Scans at Cliff
Sinan Abood, Mike Falkowski, and Steve Curelli calibrate the LiDAR scanner.
A few weeks ago I wrote a short post about LiDAR. This technology (Light Distance and Ranging) allows for precise mapping of topographical and structural features from the air, the ground, or even space. The idea behind LiDAR is that light (or more specifically, lasers) travel from a scanning device to the ground and then back to the unit. The LiDAR device can then calculate the distance the beam of light travelled as well as the time it took to return to the device, thereby providing data that can be used to create a 3D representation of the area being scanned.
Mapping inside the stamp mill's interior. Note the vegetation that can obstruct the scan.
In early May, a team of researchers from Michigan Tech lead by Dr. Michael Falkowski of the School of Forestry Resources and Environmental Sciences and including myself and fellow students Sinan Abood and Stephen Curelli, brought a ground-based LiDAR device out to Cliff to see how effective a scan would be.
Due to the timing of the scans (this took place before the field school, and clearing of vegetation, began) and weather, our choices for scanning locations were limited. We chose to set up the device in two locations: at the No. 4 Shaft rock piles located above the bluff to try out a landscape scan, and inside the stamp mill’s boiler house for an interior structural scan.
Once the LiDAR unit is put in place, it rotates 360 degrees while emitting light towards the target being mapped. At the same time a digital camera mounted on the LiDAR unit takes pictures in order to provide a color scheme to match the “point data” created by the scan. This way the data can be processed to look almost identical to its real world target.
The No. 4 Shaft's steam stack.
Both scans are currently in the data processing phase but recently we were able to create two videos showing how the data can be used to create 3D representations of the data. Due to time, the scan of the No. 4 Shaft area has been narrowed down to focus on the steam stack that sits within a large rock pile. Compare it to the photo on the right. What you will notice is how well LiDAR picks up each individual stone as well as the leaves of the vegetation at the stack’s base.
The scan of the mill interior is obstructed somewhat by the trees and vegetation lying in and around the structure. With time, these obstructions can be removed from the point data but for this demonstration I think its valuable to see just how well the LiDAR picks up even the smallest detail.
The LiDAR crew.
Here are video animations of two structures at Cliff using LiDAR technology from our YouTube site.
A Look at the Mapping Possibilities of LiDAR
Here’s a link to a great article from a few days ago in the New York Times. It’s using LiDAR (light detection and ranging) technology to create highly detailed maps of Mayan cities in Belize. The CliffMAP will also be using LiDAR to look at interiors of structures as well as some of the industrial landscape features on top of the bluff. While the work we are doing in no way matches what’s going on in Belize (we don’t have that kind of money-yet), this is an accessible article about mapping technology that could help provide context to our project at Cliff.
Take a look (you may have to copy and paste this link into your browser):
Sean Gohman
Timothy James Scarlett
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