Maintaining Connectivity in Dynamic Multimodal Network Models

Network data models are frequently used as a mechanism to describe the connectivity between spatial features in many existing and emerging GIS applications (location- based services, transportation design, navigational systems, etc.). Connectivity information is required for solving a wide range of location-based queries like finding the shortest path, service areas discovery, allocation, and distance matrix computation. Nevertheless, real-life networks are dynamic in nature since spatial features can be periodically modified. Such updates may change the connectivity relations with the other features and connectivity must be reestablished. Existing approaches are not suitable for a dynamic environment, since whenever a feature change occurs, the whole network connectivity has to be reconstructed from scratch. In this paper, we propose an efficient algorithm that incrementally maintains connectivity within a dynamic network. Our solution is based on the existing functionality (tables, joins, sorting algorithms) provided by a standard relational DBMS and has been implemented and tested and will be shipped with an upcoming release of the ESRI ArcGIS product.