The digitization of graph-based engineering diagrams like P&IDs or circuit drawings from optical sources as well
as their subsequent processing involves both image understanding
and semantic technologies. More precisely, after a raw graph has
been obtained by an object detection and line extraction pipeline,
semantic gaps (like resolving material flow directions) need to
be overcome to retain a comprehensive, semantically correct
graph. Likewise, the graph representation often needs to be
altered to achieve interoperability with established CAE systems
and to accommodate customer-specific requirements. Semantic
technologies provide powerful tools to manipulate such data but
usually require rather complicated implementation. Graphically
presentable graph based rules provide a code-free mean to ease
the interaction with domain experts. In order to be applicable
in real-world applications, both geometric and computational
aspects need to be considered. This paper explores these aspects
and demonstrates use cases of such rule graphs
