About Me

My Photo
Saint Augustine, Northeast Florida
Going public with archaeology for outreach, assistance to local governments, and service to the citizens and state of Florida. Visit our website at: http://flpublicarchaeology.org/nerc/
Powered by Blogger.

Blog Archive

Photogrammetry Basics

A Quick Overview of Processing Pictures Into a 3D Model

Screenshot of a 3D model of tabby slave cabin foundations and walls from Kingsley Plantation, Florida.

Photogrammetry,as a technique to create three-dimensional models, is a growing trend in heritage management and a new tool in the archaeologist's toolkit that is allowing for quick, accurate data collection; this digital data is easily stored and shared, making it one of the best methods for disseminating information about artifacts, historic structures, or even entire archaeological sites. This post will highlight a few of the useful software programs that you can use to create 3D models as well as a an example step-by-step of the creation of a 3D image.


At the most basic level, photogrammetry is the use of photographs to determine some kind of measurements from them. This has been a field of study since about as long as photography has been in use, gaining more momentum as portable cameras were able to be flown on aircraft. Today, photogrammetry might be a word that is applied to a number of specific techniques for remote sensing and measurement data obtained through photographic techniques whether on the ground, in the air, or even from low-earth orbit. For those of us in the field of archaeology, however, we are most often hearing the word these days in relation to software that allows us to create 3D digital models from a series of pictures. 

There are several types of software to choose from. FPAN does not endorse any particular one of these software packages. Some are open source, some are just free; for the most part it's a matter of defining your desired outcomes and matching it to the program that best fits your data collection needs. The example below is produced with Agisoft Photoscan's Standard Edition. We have found that it is a great package and gives excellent results-it's pretty easy to use once you get the hang of it, too! A few other examples of software packages/equipment that are used for this and similar purposes include:

Autodesk 123D Catch
Structure Sensor
Autodesk Recap
Acute 3D Context Capture
Drone Deploy
Blender
Sketchup
and, though not exactly in line with what we're talking about ArcGis Earth has some neat 3D things you can create/work with.

This example will serve as a general overview of the process, just to give you an idea of how this kind of software works.

The first step is to take a series of photos of an object. Generally, there should be a 60% overlap of the pictures to allow the software to tie the pictures together. You can either move the camera around the object or move the object around in front of the camera. This sounds a little bit easier than it actually is. The outcome of your model will depend on your photo set. The better the quality and number of pictures, the better the model. It can also help to have reference points included in the picture, say lettered numbers, pin flags, or other objects; this all helps the software align the photos.

Photos are taken from as many angles as possible, making sure to overlap. This wasn't hard to overlap as every photo overlaps due to the size of the headstone.


Once you have taken the pictures and uploaded them into the program, the next step is to "align" the photos. Don't worry, the program does this for you. It may not be able to align all of the photos, which is why more is better. However, as with all software programs, the more data you give it to crunch, the longer it will take. This will create the "sparse point-cloud" which will give you some idea of what camera shots were able to provide data and a first step to edit a little bit.

The sparse point cloud is generated by aligning the photos. The blue rectangles are the locations of the camera when it took the picture. You can see some random points outside of what we are trying to model.


After the photos are aligned the next step is to create a "dense point cloud". In essence, the program is defining x,y, and z coordinate locations in a space of the object you have taken a series of pictures of. This is the big framework that the rest of the model will be built on, and an opportunity to edit errant points or clear out photographic "noise" like other objects you are not intending to model.

The dense point cloud has been created. It allows for a much better visualization of what you might want to edit out and what you want the program to focus on during the next steps.


Once the dense point cloud is set to your liking you will then create a mesh frame for the object; this is sort of like connecting all the little dots together into the basic outlined structure. This gives the object shape and at this point is not just a point cloud, but a 3D object.

Those of you familiar with GIS might recognize these little triangles. This is the mesh that has been generated by linking the dense cloud points together.


Finally, the color texture is overlaid on top of the mesh framework. A few more tweaks here and there and you have yourself a brand new 3D digital model that you can then upload, share, and even let other folks download to print on a 3D printer!




There are many options for photogrammetry processing out there and a multitude of uses. We'll have more in future posts, but hope this brief introduction helped you better understand how this process works.

Be sure to follow FPAN on Sketchfab to see our projects!

Text and pics: Kevin Gidusko

Just get to the point!: The controversy over stone tools

If you want to bluff your way in archaeology, step one is to rid yourself of the term "arrowhead." In the field of archaeology stone tools of this variety are classified as "projectile points" as they were often used on a variety of tools, such as spears, and not just arrows. Projectile points are frequently found by the public, collected by hobbyists, and serve as the entry point for how many people get interested in archaeology. 

This post hopes to dig a little deeper into the kinds of information stone tools can provide, why they are so critical to the study of people in North America, and help explain why they are at the center of our current House Bill 803 and Senate Bill 1054 controversy.

1. Projectile points tell us about the oldest people to inhabit North America.

Projectile points are the oldest human made objects found in America. According to a recent Smithsonian Magazine article, more than 10,000 Clovis points (the oldest known points in the US) have been found at 1,500 locations throughout North America. The presence of these artifacts across the country are so important that the location of each and every one is mapped by PIDBA, the Paleoindian Database of the Americas. Compared to the rest of the southeast, far fewer are found in Florida, particularly south of the St. Johns River. 

Image: PIDBA click on image to view source page.

Image: Florida Department of State, click on image to view source page. 


Image: FLMNH click image to view source page. 



2. You can't date a projectile point, therefore plant materials found in the same layer as the points are critical to dating.


Image: FLMNH.
The best guide for identifying points is Ripley Bullen's A Guide to the Identification of Florida Projectile Points bar none. You can purchase a copy at the Florida Museum of Natural History's gift shop, but the good folks at the FLMNH worked hard to update the information and post the Bullen Projectile Point Collection free online. 


What makes Bullen's contribution so significant, even 50 years later, is he was the first to compile a descriptive guide of Florida projectile points using consistent terminology and by getting radiocarbon dates for organic materials found in the same strata as the points. To put it another way, rather than just basing the dates on stylistic differences, he was able to put them in chronological order based on absolute dating methods, not just relative methods. But this was only possible because the points were found intact in layers where the organic materials could be tested. 

You can't date stone, at least not at that time for when the stone was modified and made into a tool. The next best thing is to date the other materials found in the same soil where the stone was deposited. This is why it's so important that the soil around stone tools be left intact. Pollen, seeds, charcoal and other organic remains have the potential to provide absolute dates but are easily disturbed especially in submerged environments such as river bottoms.

For more on the history of the Bullen guide and it's many contributions, read the 2004 forward by Jerald Milanich found here.  


3. The public is involved everyday in helping us fill the data gaps between points.

Image: Kelly-Jane Cotter, Staff, Asbury Park Press aap.com.

Remember this kid? Noah Cordle discovered a 10,000 year old projectile point in New Jersey in 2014. Noah joined the ranks of utility workers, farmers, hikers, divers, and other history enthusiasts who came forward with their find and allowed it to be documented and recorded. In fact, most archaeological sites are not found by archaeologists. We follow up on the information given to us largely by the public, and from there through careful excavation and years of study more information about the past becomes clear.

Noah's mom had this to say:

"I think it's super cool that this happened,'' said Andrea Cordle. "But it's not ours. It's for everybody. My father-in-law died recently and he collected arrowheads, and my husband thinks this was from his father. We know his father would have loved to see it. And from the bottom of my soul, I feel it's meant to be seen by everybody.'' from APP.com.


4. The kind of stone the points are made out of tell us about trade and migration.

We got very excited a few years ago that not one, but two Cahokia points were found in Jacksonville at Mill Cove. Why is this exciting? Cahokia points originate from the Missouri/Illinois border site of Cahokia, a prehistoric village and the largest Pre-Columbian earthwork in the Americas (Monk's Mound). The points are identified by the stone from which they are made and the shape of the point. We can get the same information from other points if we know where they were found, we can connect our special places in Florida to those who traveled far to get here hundreds and thousands of years ago.

Image: Keith Ashley, UNF, from FPAN Storified feed.

Missed Keith Ashley's talk on Mill Cove? FPAN live tweeted the talk and the archive of posts can be found here with images included.


5. No one likes the idea of a box of points collecting dust on a shelf.

We hear this a lot, that the artifacts should not sit in a box collecting dust, they should be enjoyed. Many projectile points are on display, but far more are kept in curation storage facilities. When artifacts are curated, not just projectile points but all archaeological materials, they are stored in archival quality boxes and bags on shelves. They are stored so that future archaeologists and members of the public can view the artifacts, apply new techniques to be tested when discovered, and keep the collection as a whole for future study.

When a collector keeps an artifact, they are only available to those who the collector will let view. They may put them on display or keep in a box. Where I work, all to often members of the public come in with an artifact someone in the family had collected and they don't know what to do with it. The object, by being removed from its context in the ground or collection of artifacts it was found with, has lost all scientific potential. What remains is aesthetic value, and sometime educational value if it is an identifiable form that can be used in teaching collections. Most often the object is not a particularly good example of a type, and now it holds no value- not scientific, not aesthetic, and not educational.


Image: general meme search but also "Why I Belong in a Museum" post. 

When Indiana Jones responds that an antiquity "belongs in a museum!" it is a general statement that the artifact belongs to all of us. Museums are the public libraries of historical objects and the best way for the greatest amount of citizens to benefit from possession of the object. 

I get the point that objects should be freed from being in a box on a shelf. But ultimately even points that are sold and traded often end up in similar boxes on shelves. The only thing that ultimately saves them from the landfill is if they have provenience information (location) and are kept with the other objects around it from a site.


6. Points are works of art and express more than just meeting basic needs by hunting.

Projectile points are first thought of as a hunting tool, how to meet a human's basic need of procuring food. I liked the way the Smithsonian article worded it, "the Clovis point was part of a generalized tool kit—the Leatherman of the ancient world."

But points are also works of art. Using experimental archaeology, flint knappers try to understand the complicated formation processes by recreating stone tools. An excellent video by Emory University, produced by Carol Clark, conveys that people have made stone tools over 2 million year and that they are not just tools, but detailed evidence of behavior. From stone tools you can see evolving intelligence, the evolving mind.

Image: screen cap of The Minds of Stone Age Toolmakers, click for link to video.


7. Refitting flakes may be the hardest job in archaeology.

I like puzzles as much as anyone, but it takes a special mind (and I mean special) to take on refitting stone flakes back together to further understand the knapping process. It requires every piece as every piece is used to refit the tool back into the raw core it came from.

Image: Texas Beyond History, image linked to source.


When people show me a flake they picked up, thinking it was just a random flake, the refitting images pop into my mind. There may be someone trying to refit the puzzle together who will not be working from a complete set. Even the tiniest flake matters!

For more on the crazy world of refitting, for which I have an enormous respect, check out this blog post on Putting Pieces Together: Refitting Ancient Stone Tools.  


Image: The Archaeology and History Blog.


8. The frightening reality that most often only stone survives, as other fragile information deteriorates over time. 

The Windover site haunts my dreams. It is a 7,000 year old mortuary pond near Titusville where prehistoric people were pinned to the bottom of the pond approximately 48 hours after death. Windover is most famous for the collection of organic artifacts that don't usually survive on the land: textiles, human tissue, seeds and other organic materials. 

Image: Replica cast skeleton at Brevard Museum, link to original page. 

The statistic that scares me the most: two projectile points and a single flake are the ONLY stone tools recovered from Windover (Hamlin 2001). What if every site where we find a flake or a few random points represents 169 people with a vast array of organic artifacts? That is the reality behind what the two points found at Windover represent.


9. Points of contention. 

You may have noticed I reference the Bullen guide, and not one of the many guides to collecting artifacts that include price tags. That is because to an archaeologist artifacts are only worth information, never money. The market for legal and illegal artifacts is so large in scale, one recent number from UNESCO put the illegal relic market at 6 billion dollars worldwide annually. Artifact sales may seem benign, but on a global scale sale of artifacts help fund terrorist organizations such as ISIS (according to CBS but see the New Yorker article with alternative interpretations). In sum, illegal artifact trading is not stuff you want to be involved in.

Are there examples of collectors and archaeologists working together? Absolutely! On land Montpelier's Metal-Detector Expedition program comes to mind, as does the Southern Idaho and Northern Utah Paleoindian Research Program directed by Dr. Bonnie Pitblado. These programs foster mutual benefits for both professional and avocational archaeologists. However, no citizen science program that I know of allows participants to keep artifacts on state protected land. Selling of artifacts for profit is against every archaeological society's code of ethics, it's a partnership deal-breaker that can't be overcome. 

The current controversy over Florida House Bill 803 and Senate Bill 1054 comes down to ownership of stone tools. No other class of artifact is in as great a danger in the rivers of Florida, land that is state owned and protected by our 50 year old Historical Resources law (Chapter 267). Can there be a compromise that allows for collection of single artifacts from state land? Not if ownership of the artifact passes from the state to the individual, as the current bills propose.

Image: Pitblado 2014, see reference below.


10. We are not the only ones who collected and appreciated early stone tools.

There are archaeological examples where we find stone tools that predate the culture they are buried with, meaning prehistoric Native Americans were also entranced by early projectile points and would often carry them with them. Especially in Florida, stone was a limited resource and stone blades were reshaped, reused, and recycled to make maximum use of the material. I find great comfort in the idea that what fascinates us today, what we assign value and give our careers to study, was also of interest 1,000 years ago as Floridians then pondered what life was like thousands of years before them. We are part of a great chain of those who have questioned Florida's past, and we can all be part of finding the answers.



Text: Sarah Miller, FPAN staff
Compiled from information where images are cited and referenced below.
Images: cited in text 

References

Hamlin, Christine. 2001. "Sharing the Load: Gender and Task Division at Windover." In Gender and the Archaeology of Death, Bettina Arnold and Nancy L. Wicker (eds.), Chapter 7. AltaMira Press. 

Pitblado, Bonnie L. 2014 How Archaeologist and Artifact Collectors Can—and Should—Collaborate to Comply with Legal and Ethical Antiquities CodesAdvances in Archaeological Practice 2(4):338- 352.

MLK Day in San Sebastian Cemetery

We could think of no better way to commemorate MLK Day than to spend it remembering those buried in St. Augustine's oldest African American cemetery.   




San Sebastian Cemetery is located just outside of St. Augustine's Historic District.  It's only 50 feet away from the meticulously maintained Evergreen Cemetery, which has contrasted greatly to San Sebastian's often neglected and vandalized state.  Thanks to the clean up efforts of several groups, San Sebastian is in a much improved condition, allowing us to see and record what is there!  Recording involves transcribing each grave's names, dates, iconography, location, measurements, and getting detailed pictures. This past MLK Day we had 7 volunteers help us do exactly that, and 32 graves were recorded!


Being that many of the graves are unnamed or half buried, creating an accurate picture of San Sebastian can be tricky.
 Historical records also indicate that many graves were marked only with a stone, a tree or a pile of conch shells - and sometimes the piles would be moved to different locations around the cemetery!  

So, although something may look like a meaningless pile of rubble, it could actually be marking someone's final resting place and needs to be recorded.

But in addition to the mysterious, San Sebastian Cemetery is also full of the beautiful; Some marker's beauty lies in the shape of its stone while others lie in the sweetness of the homemade attempt to remember a loved one.

 


 

We will be recording at San Sebastian Cemetery every Monday starting at 11:00 a.m. for the next several months and would love it if you could join us!

Text and Photos by FPAN Staff, Robbie Boggs

Meet Elisha, the East Central Region's New Outreach Assistant!

Hello! I’m Elisha Tisdale, and I’ve just recently joined the team at FPAN in the East-Central Region as an Outreach Assistant!
 
"Hi!" from Tulum - visiting the Maya site in Mexico last year.

So, how did I get here? I received my bachelor’s degree in Anthropology from the University of Central Florida (UCF) in 2011 and am currently finishing up my Master’s Degree in Anthropology at UCF as well. I have lived in East Central Florida for over twenty years and have been fortunate to be able to participate in local archaeological projects right here at home.
 
Hiking and Geocaching in a nature preserve in Central Florida
I have been in love with archaeology for as long as I can remember. I fondly recall a pivotal career day in third grade where my timid eight-year-old self had to painstakingly write and rewrite arch-ae-olo-gist what seemed like ten thousand times to get the spelling right for my career day archaeologist paper doll. After all that work, imagine my distress when my third grade teacher didn’t even know what archaeology was! I was crushed. It has been my mission since that day to help establish an awareness for this fantastic science!
  
Cleaning headstones during a CRPT course with FPAN  
Of course, our interests evolve as we grow. Once I left my juice-boxes and multiplication tables behind me, I went on to develop a keen interest in studying human burials and human remains in an archaeological context – this area of specialization is called bioarchaeology.


I was thrilled to be asked to join the team here at Florida Public ArchaeologyNetwork. Where else could I gush on about archaeology with like-minded and interested people all day? It is crucial to promote an awareness of the importance of our history, our heritages, and of our cultural resources. Here in Florida we are blessed with a really unique story which spans thousands and thousands of years. By promoting archaeology and the protection of our cultural resources we can help preserve our history and cultural resources (and maybe inspire a few kiddos for their career days?) for years to come! 

Touring the 10 Thousand Islands

I was invited by our Southeast/Southwest offices to head down to the Ten Thousand Islands to help make some videos highlighting the cultural and natural resources in the area.

Our motley FPAN crew: Becky (W Central), Rachael (SW), Jennifer and Ashely (SE), me (NE) and Sarah (SE)!
After reading Killing Mr. Watson during our summer book club, I was excited to see some of the places in the book. Sure enough, we got to see some of Watson's sugar mill equipment left at his old property, cruise past Rabbit Key where he was buried and stop into Ted Smallwood's store, the location of Mr. Watson's demise.

Pot left from Watson's sugar production, used to boil down the cane juice.
Ted Smallwood's store on Chokoloskee Island, where Ed Watson was fatally shot by numerous residents of the area.

We also took a stroll through Fakahatchee Strand Preserve State Park to check out the local swamp environment, home to the Seminole and probably many other native peoples. Most of the hike took us along a railroad bed and gave us a great look at restoration efforts after many years of cypress logging. But we also got to get our feet wet in the swamps.

Greetings from the Everglades!
The trails can get a little wet...
Stay tuned for some great videos from the trip!

A special thanks to our wonderful guides from Everglades Area Tours for their wonderful guidance and knowledge of the area's history and environment!

Text and Images by Emily Jane Murray, FPAN Staff

Holiday Shell Edged Manicure Tutorial


The St. Augustine Archaeology Association holiday party is tomorrow night which means its time again for my holiday-inspired (and archaeologically appropriate) manicure. For those of you also wanting to strike up some late 18th/early 19th century ceramics cheer, here's a tutorial to help you get your brush on!

Blank slate

Start with layers of white

Add thick tip of red to every other nail

Alternate with green tips between the red

To give impression of shell edging, use thin white brush to paint up to nearly the edge of the red tip.

Repeat painting thin white line up to nearly edge of green tip.
Grab a trowel or another holiday prop.

Turns out holiday inspired nails aren't just fun, they're also educational. You can tell those admiring your nails they are based on Rococo-inspired scalloped rim plates, found by archaeologist on sites dating from the late 18th to the early 19th century. Most often we find blue, but plates featuring green and red rims were made between 1775-1810 (JefPat).

Shell edged rims in various colors (Image: Robert Hunter, Chipstone Foundation). 
Text and images: Sarah Miller, FPAN staff except where noted.

Public Archaeology Down Under

A few months ago while traveling in Australia I was inspired by some of the ways archaeology was featured on the streets, incorporated into the architecture, and featured on display at various historical sites.

1. From the Street

This panel looks small but took up an exterior wall above a busy covered sidewalk on George Street close to the Rocks. Archaeology had been done in advance of street improvements on the site, and this looked like an honest effort from the contractors to show what archaeologists found out as a result of their excavation. I'd LOVE to see more urban archaeology displays like this in the cities I visit.

Overall panel.


Close up on maritime industries, economic tie to the area. Project area in red.

Close up of the project area location on historic drawing.

Tools attributed to the Gadigal, Sydney Cove's first inhabitants, found in the lower layers and predate European settlement.

I did look up the site- for more on the project see the GML website.  

2. Integrated into the Architecture

The scale of the next example is difficult to illustrate, but from the pictures you can see the Youth Hostel with silver screens raised in front of the structure. The screens illustrated the size and scale of a former structure left intact UNDER the contemporary building. For more on the site, check out the Big Dig Archaeology Education Centre website.
View from the street.


Open features in situ with wire horse and silver standing screen to illustrated architecture.
Panels and maps help orient the visit to the site.


Cleaver use of wire sculptures to illustrate livestock, note Big Dig Archaeology Education Centre in the background.

More views of interpretation for the public at the YHA site.

Artifact cases feature ceramics, glass, and personal objects of various materials found during excavation.



More open features and interpretation under the main YHA structure.

Chain mail coin purse.

Personal objects such as tooth brushes, syringe, pins, and studs.

3. Artifacts Big and Small on Display

In both Sydney and Canberra we saw archaeology featured prominently in house and national museums. 

 Cadmans Cottage (1816), oldest standing structure in Sydney.







I saw my one and only headstone in Australia at the Rocks Discovery Museum, that of George Graves died 1768. I also learned what a Sailor's Palm was, something like a thimble worn on the pal, to push needles through sailcloth. Many of the domestic artifacts were familiar to me, as ceramics and glass found in Australia and America had British origins. The kids section featured a "Make Your Own Exhibit" activity capitalizing on the educational value of objects. Finally, up on the top floor the museum exhibited works from an annual reconciliation art challenge. Out of respect for the artists I took no photos except of the promotional flier. But it was really the first time I saw the theme of reconciliation explained, and the theme continued throughout all other natural and cultural places we visited. A few of what we in the US would call prehistoric artifacts were on display. The canoe and stone tool styles looked completely foreign to me. 
















National Museum of Australia in Canberra

The National Museum of Australia in Canberra featured two displays I'd like to mention here. One is a display featuring John Mulvaney's tools, considered the father of Australian Archaeology. While I was impressed with the screen and trowel on exhibit, in my search for a better picture I found 58 objects once made or used by John Mulvaney (check 'em out!). The other exhibit I found fascinating was over 300 convict love tokens on dark display (literally, some of the lights were not on). Prepare to be disappointed by my shots from the museum, but on an extremely positive note the museum has a fantastic interactive Convict Love Tokens website where you can learn more about these endearingly personal, modified objects.

Just one of the 58 objects owned by the museum by John Mulvaney.

Convict Love Tokens on display


 Told you- you're gonna wanna visit the Convict Love Tokens website to get a better look.

Text and Photos: Sarah Miller, FPAN Staff

- Copyright © Going Public - Skyblue - Powered by Blogger - Designed by Johanes Djogan -