Considering Uncertainty in Archaeological Predictive Modelling: A Case Study in Southern Rhineland-Palatinate (Germany)

摘要

Most archaeological predictive models lack significance because fuzzincss of data and uncertainty in knowledge about human behaviour and natural processes are hardly ever considered. One approach to cope with such uncertainties is utilization of methods, which base on approaches of the probability theory like Bayes Theorem or Dempster-Shafer-Theory. In our case study we analyze an area of 50 km2 in southern Rhineland Palatinate (Germany) near the Celtic oppidum "Hunnenring" by use of Dempster-Shafer's theory of evidence for predicting spatial probability distribution of archaeological sites. This technique incorporates uncertainty by assigning various weights of evidence to defined variables, in that way estimating the probability for supporting a specific hypothesis (in our case the hypothesis presence or absence of a site). Selection of variables for our model relies both on assumptions about settlement patterns and on statistically tested relationships between known archaeological sites and environmental factors. The modelling process is conducted in a Geographic Information System (GIS) by generating raster-based likelihood surfaces with a cell resolution of 10 m for the six selected variables 'distance to water', 'distance to road network', 'distance to graves', 'slope', 'landforms' and 'geology'. The corresponding likelihood surfaces are aggregated to a final weight of evidence surface, which results in a likelihood value for every single cell of being a site or a non-site. Finally the result is tested against a database of known archaeological sites for evaluating the gain of the model. To address the high potential of soil erosion processes of the low mountain parts of our study area a model was developed which allocates erosion and deposition zones to those areas. The combination of this model with the predictive model yields a more differentiated estimation, especially with regard to the suspected potential of archaeological remains being conserved until present.