Over the past two days we’ve exposed the top surface of the house at the site in the cranberry bog.  Roughly oval in shape, it manifested as a dark soil surface ringed by lighter subsoil deposits. It also had several post moulds (dark soil stains left from upright tent poles) around its circumference as well as internal rock arrangements.

Image of the oval dwelling surface (the floor of a wigwam-like structure), outlined with string. This floor was very difficult to discern and involved careful scrutiny of changes in soil colour inside and outside of the structure (these don’t replicate well in photographs, hence the string). The raised baulks will provide a record of soil layers as they transition through the house floor. Note the dark colour of the interior of the structure.  For a better picture you will have to read Gabe’s upcoming doctoral dissertation!

Mapping these features is difficult and time consuming; every aspect of the feature must be drawn accurately. Archaeologists typically do this with pencil and graph paper (each sheet usually depicts two side-by-side grid units). When we get back from the field, each of these sheets must be scanned and loaded into illustration software to be traced by hand. The traces must then be digitally concatenated and formatted to produce a publication quality map. This process can take days, and it is a source of many transcription errors introduced as hand drawn images are converted to digital format.  This year, however, we are using iDraw on our iPads to map features and draw soil profiles.

Here I plot features on the iPad as Gabe measures them in relation to the grid system. In my experience, using the iDraw app is as fast as using traditional pencil and paper.

The iDraw app is ideal for archaeological mapping because the canvas (background) can be set to a millimeter grid that perfectly mimics real graph paper.  From there producing a map is as simple as drawing on regular graph paper (we use a stylus to draw on the iPad).  However, iDraw is also a fully featured vector-based illustration app, meaning that it has the ability to produce a completely formatted and polished image (which is near-publication quality) as you are drawing it. We use the iDraw pen tool to do most of our mapping; by holding and dragging each plotted point you can produce curves and other complex outlines. When the “polygon” is closed it automatically fills with the colour of your choice, leading to instant colour coding of rocks, hearth features, etc. Because much of the formatting required for publication can be done while you are mapping, such software will save many days of scanning, tracing, and formatting time in the office.

A screen capture of part of the finished map on iDraw. All of the formatting was done in the field during the mapping process. You’ll have to see Gabe’s doctoral dissertation for the complete map!

We found the layering function of the software particularly helpful; it can be used to set background layers (such as our grid unit system) that can’t be modified while drawing other features on a different layer. In our setup the grid units are reproduced on Layer 1, the house outline and other soil features on Layer 2, the rock features on Layer 3, the baulk system on Layer 4, and elevations on Layer 5. This way there is no danger of modifying the data in previous layers by accident as you draw.

Layers in the final map. Note the elevations plotted for each feature and grid pin.

When I originally began thinking about digital data collection in the field, mapping was the issue that always seemed to be the most daunting and problematic. Existing handheld devices were too small and inaccurate and the available drawing software was rudimentary. With new tablet computers and apps such as iDraw, there is little reason to continue using pencil and graph paper in any archaeological field project where efficiency, accuracy, and cost effectiveness are goals.

My archaeological colleague at the Museum, Dr. Terrence Clark, is also in the field this year. He is conducting a community archaeology project with Shíshálh band members on the Sunshine Coast of British Columbia. Yesterday, he sent me this email to post on the blog:

“The 2012 field season in underway and the action is in full swing. We are lucky this year to take part in a training program where high school students from the Shíshálh Band are partaking in the excavation. These five youngsters are right in the middle of things, having been equipped with all the tools and the know-how to be real archaeologists.

Terry and his crew travel to the site (Photo by Andrea Gilchrist).

The sun is shining and the breeze is cool; the only thing sinking our enthusiasm is our unfortunate luck with boats. Despite our high expectations of the rented zodiacs, they have not performed according to plan. A piece broke in the motor of our 5-man zodiac right in the harbour of our camp and despite our remote location there happened to be a friendly fisherman and his wife nearby who towed us into town. We were able to order the new part without too much difficulty and now that motor is back in action. Our 8-man zodiac, however, had not gone as far as breaking down but wasn’t performing to its maximum potential. After finally reading the manual it turns out the tilt wasn’t put on properly but with the help of a wrench it too is ready to go. Fingers crossed, our boat troubles are over!”

We’ve spent the last two days working at a site near the head of Port Joli Harbour, instead of at our house floor site in the cranberry bog. We are digging here to gather some animal bones, datable remains, and artifacts to assist us in filling in the cultural sequence for the harbour.  The landowners kindly gave us permission to dig on their property, and we are very grateful to them for letting us spend several days on their front lawn.

Natalie digs into the nicely manicured lawn. The mottled soil (note the alternating colours) indicates a mixed deposit consisting of cultural soil and subsoil.

The site has a spectacular view and was the former location of a vegetable garden which was used for decades.  While we knew the site would be disturbed, previous reports indicated that there were undistributed deposits beneath the plow-zone. Unfortunately this has proven not to be the case and the entire deposit appears to have been affected by ploughing.

The crew takes closing depths after excavating three units. Note the undulating nature of the subsoil, caused by repeated ploughing.

Regardless, we recovered enough animal remains to date the site accurately (we use terrestrial mammal bone for radiocarbon dating), and we found an array of decorated ceramics and chert (stone) artifacts.  We didn’t recover enough animal bones to reconstruct the site’s subsistence patterns with certainty, but with a radiocarbon date and several diagnostic artifacts, we will be able to say much about how the site fits into Port Joli’s archeological sequence.

A selection of artifacts from the site. The two artifacts on the left are scrapers, used for working wood, bark, and bone. The two items on the right are projectile points, probably arrowheads.

Going digital has created some challenges managing and backing up the data we have collected. We have spotty cellular coverage in Port Joli, so sending our data over the cellular network wouldn’t be reliable. This means that we must store our data on the iPads throughout the day and then backup the data at night. The only problem with this is that we are relying on the stability of the iPads to protect our data. If they malfunction or are damaged in the field, we could conceivably lose some information; however, I view this as no more risky than using a digital camera for fieldwork.

Gabe takes some notes during lunch break.

We use a hierarchical system to store our data, managed through a combination of PDF Expert and Dropbox. Every form is labeled with an alphanumeric sequence denoting the unit and level, and whether it is a “draft”, “complete”, or “flattened” document (flattened to preserve any maps – see previous post). All of the day’s notes are stored in a general documents folder in PDF Expert; every crew member also has a special folder that is networked to a Dropbox account.  When we return home in the evening, completed forms, maps, and draft forms (unfinished forms) are copied by each person to their specific Dropbox folder, and then they sync, or “push” these changes to the Dropbox account.

Our file management system in PDF Expert. Here the crew-member’s folder has already been synced to the project Dropbox account (denoted by the green check mark). We organize the forms on the iPad by unit, hence the number of folders. Note also the master unit level record form, which we use as our “template” for all new levels.

This process is streamlined within PDF expert, as the app is designed to work seamlessly with Dropbox. The app notifies you when you have changes to be synced and when all of your changes are up to date within Dropbox. Syncing is achieved simply through the push of a button.

My field laptop is also networked to the Dropbox account through their downloadable software. I don’t even have to sign in;  the account is always active when I am online and it notifies me when someone has modified or uploaded data to their folder. From there it is an easy task to download the day’s files from Dropbox to the laptop’s hard drive. This creates a triple backup system – the files are stored on each crew member’s iPad, they are archived in Dropbox, and finally they are backed up nightly on the project laptop.  This is about as secure a digital management system as we could hope for.

Dropbox notifies me when a file has been uploaded. I then transfer these to the project laptop for safekeeping.

As I have described in previous posts, progress at the main dig site has been relatively slow and artifact densities have been low.  Today, however, we finally encountered productive cultural deposits. This afternoon we uncovered the first portions of the house floor we have been searching for, including a hearth located within the dwelling.  We also encountered an interesting projectile point and several large pieces of decorated pottery.

Natalie and Gabe dig in deposits above the presumed house floor. The test unit from 2009 can be seen in the background behind Gabe.

All of the materials we have recovered from these upper deposits indicate that the soil layers above the house floor probably date to the Late Maritime Woodland Period, sometime between ca. 1350 B.P and ca. 500 B.P.

Natalie holds the large Late Maritime Woodland projectile point she discovered today. The tip was broken in the past and was not found with the point.

A large rim sherd (a fragment of pottery with an intact rim) with intricate decoration. This was from a very large pot, and the decorative motif matches pottery recovered from other sites in the harbour.

This was a surprise to us because the artifacts from previous excavations at the site, and radiocarbon dates from charcoal in the deposits, indicated that the large adjacent shell midden was occupied in the Middle Maritime Woodland Period, between ca. 1600 and 1450 B.P.  We know from a previous test pit and radiocarbon date that the house floor also dates to ca. 1450 B.P. So, it appears that there was a relatively ephemeral Late Maritime Woodland occupation after the Middle Maritime Woodland house floor and midden were deposited. This is interesting because it suggests the site was being used during both of these periods, but seemingly in very different ways, perhaps at different times of the year  (i.e. there does not appear to be a shell midden associated with the Late Maritime Woodland deposits at the site).

We are slowly exposing the archaeological deposits at AlDf-30, where we are searching for a Middle Maritime Woodland (ca. 1450 B.P.) house floor that we encountered in a 2009 test pit. We haven’t  made our way down to this cultural layer yet, and the overlying deposits have had low densities of artifacts. However, we have encountered a few artifacts and features which need to be mapped, and this has given us the opportunity to test the use of PDF graph paper on the iPad.

Gabe maps a feature using PDF graph paper on his iPad.

You may remember that the forms we are using incorporate PDF graph paper; we are using PDF Expert to draw our unit level plans directly on to the PDFs. The app has a robust annotation and drawing function that we use to its full capacity.

Jesse uses PDF Expert to set the line colour and style before plotting a feature.

We plot the features and artifacts exactly as we would draw them with a pencil and graph paper –  by placing a dot at every plotted point, and then connecting those dots to fill in the outline of the features. So far, it has worked very well. We use Jot styli to plot the points, but we have found that dust often gets caught between the stylus disc and the screen, scratching our iPad screen protectors. We are coming to the conclusion that a finger works best (that’s what the iPad was designed for), and the zooming functionality helps with turning fat fingers into small lines.

An example of one of our unit plans drawn on PDF graph paper using the iPad.

Once we finish drawing the plan, we have to save a “flattened” copy of the form. This can then be imported into most standard illustration packages. This will save us countless hours back in the lab; normally we scan hand drawn maps, import the scans into illustration software, and then digitally trace every line to produce a publishable image. With the PDF forms, we negate the scanning and tracing necessary to produce the maps.

If you are testing the forms, be sure to first preserve an unflattend copy – flattened forms will not allow data to be imported from the form fields automatically.  For those of you trying out the forms, please let us know how you are doing!

Final image after brief processing with illustration software (ca. 5 minutes).

The last two days have been beautiful in Port Joli. Our time at the site has been extremely pleasant; the trees surrounding the midden provide great shade from the sun and a cooling breeze has kept the mosquitoes away. Progress has been slow, but we believe we have reached the first intact cultural layer of the deposit, which may be a dwelling floor (hopefully I’ll post more on that tomorrow).  Meanwhile, Dr. Konrad Gajewski and his graduate student, Karen Neil, from the University of Ottawa, have been very busy. They have been sampling a bog/fen that surrounds the archaeological site to assess climate change over the period that it was occupied.

Today they used a “Livingstone Corer”, a hand-operated device that is pressed into the bog/fen to remove a core, or cylinder, of sediment from its bottom. Over time, organic remains, pollen, and other debris accumulate at the base of the bog/fen; by meticulously analyzing this record of sediment they can reconstruct the vegetative history of the area and, by proxy, changes in climate. They removed a core over 80 cm long from the bottom of the bog.

Konrad, Karen, and Jesse (from right to left) push the corer deep into the bog sediments. This is often hard work, as the deposits can be very dense and compact.

The sample is carefully removed from the corer.

The sample is carefully measured and described. It is covered in plastic wrap, then tin foil, and is finally placed in a PVC tube to protect it during transport to the lab.

We are extremely honoured to have Konrad and Karen join the project; their palaeoclimate lab is world-class and their work will play a crucial role. Reconstructing the local environment when the sites were occupied is critical to understanding the development of human adaptations in the area. We will be collaborating closely with them to compare the record of climate change to the archaeological sequence from Port Joli.