Comparison and Benchmarks for Import of VPF Geographic Data from Object-Oriented and Relational Database Files

This paper presents some of the advantages accrued from adopting an object-oriented (OO) data model versus the relational data model when representing and managing a Vector Product Format (VPF) database, specifically the Digital Nautical Chart (DNC) for Norfolk Harbor, Virginia. An OO-DNC prototype viewer capable of importing, displaying and editing DNC feature data both from relational-format and from object-format files was developed using the Smalltalk language. The differences in performance between the relational import and the object import were then compared across several DNC coverages. The results indicate a significant increase in performance when adopting the OO paradigm; specifically the OO-DNC viewer imported feature data from objectformat files from 6 to 15 times faster than from the relational-format files. It should be noted that these figures are NOT the result of comparing a commercial objectoriented database managment system (ODBMS) against a commercial relational database management system (RDBMS), but rather the result of reading both relational-oriented and object-oriented data file formats using an object-oriented program written in Smalltalk. Nevertheless, we feel these results indicate a significant functionality and performance improvement can be obtained by using an OO framework for the data and software.