Urban Mapping by Aerial Photogrammetry using UCD Digital Camera or RC30 Analogue Camera?

Generalization is a prevalent concept in Cartography to which has been added new aspects such as model generalization with developments in GIS. Increasing demand for tailored and ubiquitous geospatial services like wayfinding, makes the context-aware generalization a noticeable research area in GIScience. Most of the wayfinding services use the network data model as the main spatial data model for their analyses. Whatever data or information that characterizes the situations relevant to users, systems and applications, can be considered as context. A context-aware service is as a service which can sense user, environment and device’s situations and respond to user requests concerning contexts to fulfill the user`s needs better. From the GIServices perspective, the context of a query could be the location of the device, environmental settings that query is made in, the time, the activity of the user, user`s personal information, the user`s favorites and information needs, the user`s cognitive map of environment, the mode of travel, the purpose of travel and the device’s technological specifications. In this paper, we propose and implement a method for context-aware network abstraction and generalization for presenting routes to the user. In this method, landmarks, POIs, personally meaningful places and current user location together play the seed role in the abstraction and generalization process. Network Voronoi Diagrams are used in this thesis for network partitioning with aforementioned places as generators. Edges and nodes which are in a voronoi diagram will be abstracted to a node in the next generalized level in the hierarchy. Repeating this procedure will produce other levels of hierarchy, based on selecting most salient generators in each level and use them as generators to form the next level. This hierarchical structure will be used for presenting routes.