When dealing with a large stratigraphic data set, it is difficult to get a general idea of the excavation's main features and their chronological sequence because the Harris diagram will become very big. During data analysis, archaeologists combine individual stratigraphic units to form groups: For example, all the postholes belonging to a building are allocated to a group. Often lower level groups are aggregated to create higher level groups, resulting in an overview display of the main features of an excavation.
This paper will present a new computer program which does not only provide various methods for defining and checking stratigraphic units and their relationships but is also capable of working with a hierarchy of groups. An automatic Harris matrix layout algorithm was developed visualizing stratigraphic relationships by means of orthogonal lines and allowing to either expand or contract user-defined groups as required. Furthermore, phases can be integrated into the layout concept as well.
Key words: Harris Matrix, stratigraphy, graph layout, relative chronology