Geography's role in archaeology

By Lance Carlson

So many times, people come to me and ask, "What does a college student of geography do?" The first thing I must explain is that the field of geography is much different than the world it is portrayed to be on shows like Jeopardy. Geography is more than memorizing the capitals of every state in the union and the names of every country on earth. Such facts require mere memorization.

Geography used to be purely descriptive, 'drawing maps and representing places with symbols and scales. Today, geography is one of the fastest moving disciplines, which explains, analyzes, manages, and even predicts! Yes, in some ways geographers are like fortune tellers. They read special types of maps to predict what may happen in the future. In business today, geography is one of the hottest topics. In dealing with demographics, land values, site locations, environmental hazards, and much more, geography is utilized and has a proven track record. After all, business wouldn't use it if it did not produce a level of utility greater than what it costs. What does it do for archaeology?

Anything having to do with spatially referenced data falls under the auspices of geography. We have implemented geography at the Aucilla and didn't even know it! The ARPP has obtained aerial photography of the Aucilla River in stereo coverage. Stereo coverage simply denotes that when viewed under a mirrored stereoscope or used in conjunction with a zoom transferscope, the z-coordinate jumps out at the viewer; in other words, the viewer has a three dimensional perspective of the terrain. This has proven helpful in finding archaeological sites in other projects.

Within the ARPP I have taken these photos, which are at a very large scale (1:9600), and transcribed them onto paper. This has allowed us to gain much better information on sites for development of site maps since the best maps heretofore were USGS 1:24,000 series. Detail in a such a smaller scale map (small scale shows large area) is too crude for our purposes.

The next step in geographic technology is to develop a Geographic Information System (GIS). GIS is a computer mapping and modeling program. A good example of this is ESRI's Arc/Info program which is currently utilized by many planning agencies around the world. Many people compare GIS with AutoCAD, because AutoCAD allows one to draw maps. But GIS is different and more powerful in the sense that it can be manipulated by its database, and this gives GIS it's predictive capability. Beyond obtaining hardware, software, and technical proficiency in a GIS program, one must ask what it can really do. The process begins with the base map produced from the aerial photographs. This base map is taken to a digitizing board integrated with the workstation that is running the Arc/Info software and digitized. The important information to have at this point deals with obtaining solid ground control points in the field. The way in which good ground control points are obtained is by utilizing a Differential Global Positioning System (DGPS). DGPS reads latitude and longitude coordinates and can be accurate to within a foot or less. Usually a solid topographical or man-made feature is chosen that can be referenced on the map as well as the ground. This is where the coordinates are shot.

The next step comes in the computer lab. The lat./long. coordinates are transferred to Universal Transverse Mercator coordinates (UTM), which the Arc/Info GIS reads. This is all done on the digitizing tablet and the workstation. Now the base map is spatially referenced with ground control points. The actual digitizing or drawing of the map comes next. Using the digitizing puck, the outline of the map is traced by a sequence of many tics (like dots), often over 10,000 on a single base map. The system draws the map by utilizing these tics, nodes, and polygons.

Once digitized, this map can be blown up, reduced, and manipulated in over a thousand ways. It is much different then drawing a map by hand and having the final product being set in stone.

I hope to create a three dimensional computer model of the Nutall Rise basin, and obtain bathymetric data that is also spatially referenced for inclusion into a GIS. This would allow us to pinpoint excavations in the river. Then every time a unit is set or an artifact is found, a spatially referenced measurement will be taken using a GPS and bathymetric profiler.

The important thing to keep in mind is that whether on land or under water, spatially referenced data falls within the discipline of geography. And it is Geography that is poised to be on the most powerful and useful tools in the near future. Its potential applications in archeology are just beginning to be appreciated.