Integrating legacy plant and process information into engineering, control, and enterprise systems may significantly increase the efficiency of managerial and technical operations in industrial facilities. The first step towards the pursued data integration is the extraction of relevant information from existing engineering documents, many of which are stored in vector-graphics-compatible formats such as PDF. Accordingly, this paper is aimed at proposing a novel methodology for the automatic extraction of structural and connectivity information from vector-graphics-coded engineering documents. A case study of a piping and instrumentation diagram (P&ID) demonstrates the reliable performance of the approach for the recognition of symbols, annotations, and underlying connectivity.