Rule-based search in historical text databases - Visualization techniques

The project Rule-Based Search in Historical Databases with Non-Standard Spellings (RSNSR, Pilz et al. 2005) will provide an online-available search-engine that can be used by interested amateurs as well as professional linguists. Parallel to the implementation of a customizable software architecture to support an efficient search functionally recalling all relevant historical spellings of a modern word in the underlying search text, there is an ongoing research focusing on the construction of rule bases and distance measures (Kempken et al. 2006) in reference to historical epochs or isoglosses. In a recent paper (Kempken et al. 2007) we describe several tree map techniques used to visualize among other aspects the productivity of rule sets in deriving non-standard spellings in old German texts.