How do archeologists know where to look for sites?
A Geographic Information System (GIS) is a powerful analytic tool that can make regional data more useful to archeologists. A GIS is used to create a computerized layer cake of spatial information about an area, each layer representing a single spatial attribute. The layers are all entered with the same coordinate system so that they are georeferenced, for example, compared with one another. The different layers can be things like roads, streams, soils, elevation, etc. Information is represented in the form of points (such as archeological sites), lines (such as roads or steams), or polygons (such as a soils or a geology map.)
GPS data from Fort Washington Park in Maryland. Red points are gun positions, the brown line is the parapet (Historic Preservation Services, NPS)
The Global Positioning System (GPS) is a technology that greatly benefits archeology because it helps show exactly where a site is located. The GPS is a constellation of 24 well-spaced satellites that orbit the Earth and make it possible for people with ground receivers to pinpoint their geographic location. A portable GPS receiver obtains signals from the satellites to calculate the user's position anywhere on earth. The locational accuracy is anywhere from 1 to 100 meters depending on the type of equipment used. GPS allows archeologists to determine exact location coordinates in the field. Archeologists can map sites and their environments can be mapped quickly and accurately using GPS to measure control points. Based on the set of on-site readings that the GPS receiver generates, archeologists can locate sites as single point coordinates, or as areas, or as corridors with many points. GPS data can also be transferred into GIS databases, making the GIS even more precise and powerful.
High Elevation Archeological Survey in Pacific Northwest Mountain Ranges
Archeologists have cooperated to develop and implement an archeological site survey and recording protocol to explore spatial, temporal, and formal aspects of prehistoric archeological sites in three national parks that span the Northwest Coast and Plateau culture areas.
For your information
Resources Mapping and Geographic Information Systems (GIS)
Learn about National Park Service programs for locating and mapping cultural resources using advanced computer technologies.
Learn more about the workings, history, cost, and applications of technologies available to archeologists, specifically:
- Remote Scanning: Aerial Photography, Aerial Infrared Photography, Thermographic Infrared Multispectral Scanner (TIMS), and Imaging Radar
- Noninvasive Tests: Soil Resistivity, Ground Penetrating Radar (GPR), Magnetometer, and Geophysical Diffraction Tomography
- Mapping: Global Positioning System (GPS) and Geographic Information Systems (GIS)
- Artifact Interpretation and Replication: Virtual Reconstruction, 3-D Scanning of Artifacts, Rapid Prototyping and Sintering (making solid reproductions from computer data), and Determining Ages and Sites of Artifacts
- Site Preservation: Electron Microscope and Fluron Light