GIS: What Is It?

Welcome back, Xplorers! Today, we’re bringing you another edition of our ongoing series telling you a little bit more about the different aspects of Cultural Resource Management. Good CRM work takes a lot of people who are talented in a lot of different areas, and there’s always something new to explore.


Today’s topic is GIS — Geographical Information Systems. And if you’re thinking, “Well, I know what all three of those words mean, but what on earth do they mean together like that??” don’t worry, we’ve got you covered!


Aa aerial photo of shovel tests we performed

GIS technology comprises some of the most innovative and fascinating tools we use in the CRM field today. It offers us powerful new ways to visualize information we collect about landscapes and archaeological sites. From mapping to analysis, GIS tech enables us to develop a greater understanding of the cultural resources all around us than ever before.


At TerraX, we have two team members dedicated to meeting our GIS needs, and we’re grateful for both of them! We couldn’t perform the work we do without our GIS specialists, and that’s why we’re so excited to share a little bit more about what they do today. Are you ready to dig deeper? Then let’s go!


Even Better Than Google Maps


So what exactly are GIS maps? In the simplest terms, GIS maps connect the “where” of the location you want to look at to the “what” or a specific dataset. They allow you to observe patterns across sites and understand how objects, structures, and other essential resources relate to each other spatially. As you can imagine, GIS is useful in a wide variety of industries!


Going back to its very earliest days, GIS essentially came into being alongside the invention of the computer. As soon as computers arrived on the scene in the 1960s, cartographers began to explore their potential for increasing our ability to represent spatial data visually. Both companies and nonprofit organizations began investing time, effort, and money to expand digital map making capabilities, and GIS began its long road of evolution.


At the end of the decade, in 1969, Jack Dangermond and his wife, Laura, founded the Environmental Systems Research Institute, Inc., more commonly known as Esri. Dangermond and company went on to develop the ArcGIS software, which is the GIS software most commonly used for GIS mapping around the globe as well as here at TerraX.


ArcGIS software is unparalleled in its ability to help users take data and represent it visually. As you can imagine, ArcGIS is incredibly useful for anyone whose work involves going out into the field! It’s widely used by land planners, government agencies, hospitals, construction, environmental services, and — yes — archaeologists. Anyone who needs to analyze spatial relationships across land formations is using GIS!


How Is GIS Useful for Archaeology?


We’re so glad you asked!


GIS is useful for archaeology in all kinds of ways — beyond just showing us maps of the areas where we’re supposed to dig! Remember when we said that CRM work takes careful planning, especially when it comes to executing digs? GIS is a critical part of that planning process.


Before we head out into the field to start digging, our GIS mappers are already hard at work, but to understand what they do, it’s important to take a step back and look at a few key terms. When we first begin a new project with a client, we have to establish three key boundaries: the limits of the actual project, the Environmental Survey Boundary (ESB), and the Area of Potential Effect (APE).


Let’s take a bridge project, for example. If an engineering company requests our services before they begin repairs to a bridge, we have to think about these three boundaries.The limits of the construction are restricted to the bridge itself and the land the bridge is immediately connected to. The ESB, however, is larger, and contains the road on either side of the bridge and a certain buffer around both (most often a 60 meter buffer on both sides of the road and bridge). This includes all land formations, vegetations, or other features in the surrounding area. Finally, the largest project boundary of all is the APE, and that encompasses the entire area that could possibly be affected (whether visually, noise, or environmentally impacted) including all land that may be disturbed by the construction crew.


A historic map with the project area labelled

Okay, so we have three distinct boundaries for any project — how on earth can we demonstrate for our clients and field crews exactly where those boundaries are? Through GIS, of course! Our GIS mappers will take a look at the relevant regulations for the state where the project is taking place and create clear and accurate maps with the boundaries labeled. That way, we can show our clients exactly how much space we’ll need to survey to comply with all state and federal laws, and we can go ahead and get ready to work!


But wait, there’s more! Once the client understands the scope of the area we’ll need to survey, it’s time to plan out our shovel tests, and for that, we need our trusty GIS mappers once again. When we decide where to dig, we use a grid system and make sure to place our tests a specific distance apart, again based on state regulations. They’ll create clear images that show the exact locations where our field crews should dig, which allows us to save valuable time and energy in the field.


The Fun Doesn’t Stop There!


Hopefully we’ve done a good job of showing you how GIS is useful in the pre-planning process, but the truth is, it doesn’t stop there. Our GIS mappers come back into the process in a big way when we start preparing full reports for our clients.


An aerial photo with shovel tests plotted

When we prepare reports for submittal, we start by including those initial maps that depict the project boundaries, ESBs, and APEs, but we also apply those boundary graphics to historic aerial photographs and topographic maps, and this allows us to compare how both land and development has changed over time. We can look at how landforms have grown and changed over decades, and we can observe whether any structures have been built, moved, or destroyed within the boundaries of the project. Finally, we’re able to show clients exactly where we conducted shovel tests and whether those tests were positive or negative for cultural materials.


It’s truly difficult to overemphasize how important this information can be! By understanding how survey areas have shifted over time with the accuracy we can achieve with GIS, we can put together more robust historical contexts than ever before. We can see how people and people groups have lived on the land and come to understand old lifeways in a much more comprehensive way, and that, in turn, allows us to be much better stewards of our shared cultural resources.


We Can’t Imagine Working Without GIS


Without GIS specialists, CRM work would take a tremendous amount of time and effort, and unfortunately, much of that time would be wasted. We’re so used to using GIS as an essential tool that it’s easy to forget, but if you go back to the early days of Cultural Resource Management, things were a little bit different.


As you may remember from our earlier post, CRM began in the 60s. While computer technology was on the rise at the time, it simply wasn’t accessible on a large scale yet. That meant that most archaeologists were working with hand-drawn maps. While we don’t wish to slight any cartographers of yester-year — their work led us to where we are today! — you can see how that might lead to some mistakes and inaccuracies.


For example, when logging the locations where artifacts were found, archaeologists working before GIS technology became widespread would often limit their site descriptions to vague 1-mile or 1-acre wide areas. This lack of specificity made it incredibly difficult to relocate sites and continue conducting investigations. Now, however, we’re able to pinpoint much more precise locations and keep much better records of where artifacts have been found, making our work much easier and more accurate.


Yup, GIS is pretty much essential for modern-day Cultural Resource Management. We know we couldn’t get along without it!


By the way…


Before we end this post, can we just take a second to shout out our fabulous GIS specialists? Heather Draskovich and Terry Barbour, y’all are doing incredible work, and we’re so grateful to have you on our team!


And there you have it! Just a little overview into the wide world of GIS. We sincerely hope you enjoyed this post! If you learned something new today, we’d love it if you would share this post with someone else! And please feel free to reach out to us on social media — you can find us on Facebook, Instagram, or LinkedIn. Let us know if you have any questions or comments! And stay tuned — next week, we’re bringing you an in-depth look at one of our biggest projects.


Until then, keep learning, Xplorers!


— The TerraX Team