Date of Degree
PhD (Doctor of Philosophy)
First Committee Member
Second Committee Member
Third Committee Member
Fourth Committee Member
This dissertation investigates three topics related to movement and events associated with geospatial barriers. This research makes a unique contribution to geographic information science (GIScience), by examining how boundaries influence the interactions of other geographic features and to location-based services by bringing a GIScience perspective to geofence services. Chapters 2, 3, and 4 can be considered independently as journal articles. Each of these chapters builds on the previous. Chapter 2 serves as the base by examining geospatial barriers and impedance events associated with these barriers. The relationships between barriers, the features they protect and the features that they hinder are formalized in an ontology design pattern (ODP) that also includes events associated with these features. Algorithms are written to demonstrate the ODP can be used to answer queries about the presence or absence of barrier events.
Chapter 3 transitions from physical boundaries to digital boundaries by examining geofences, a location-based notification service. Interaction between users and multiple geofences are investigated when the configuration of geofences differs (i.e. disconnected, partially overlapping, and completely overlapping) and when geofences are independent or dependent (a rule states that the activation of geofence Y depends on users having visited geofence X). A geofence system is prototyped in an iOS environment and used to further evaluate user-geofence interactions. Chapter 4 expands on the topic of location- based notification regions by investigating what is required for a geofence system to handle events. How changes in conditions (e.g. the spreading of a flood or movement of a fire) interact with geofences and users and what new categories of interactions are required to handle these changes are discussed. The proposed system is applied to a scenario of flooding on multiple rivers interrupting the transportation network.
Boundaries are a ubiquitous feature in geography. Frequently, boundaries are thought of in terms of political jurisdictions, demarcating countries, or outlining the extent of some phenomenon (e.g., flood waters). However, boundaries are also places where things change and interactions occur. These changes and interactions are especially apparent when natural hazards are considered. Boundaries, marked by floodwalls, protect buildings from floodwaters. Movements of wildfires mean location based alerts must be provided to citizens who are in the path of the blaze. This dissertation focuses on how boundaries influence these changes and interactions. Chapter 2 examines barriers, such as floodwalls and develops a model that will allow barriers and events to be better represented in a computerized mapping environment. Three features and four different barrier events are distinguished and there relationships defined, allowing question answering. Chapter 3 examines how individuals interact with a location-based notification system as they move through space and how this system can be designed to provide notifications based not only on where they are currently, but where they were previously. A smartphone app is developed to test these interactions. Chapter 4 continues to study location-based notification systems, and looks at how they can be used in situations that are changing, like during catastrophic flooding. A scenario drawn on an account of someone experience during the 2008 Iowa flood is used to explore how users, hazards, and notification regions interact.
Barriers, Boundaries, Events, Geofences, Location-based services, Ontology design pattern
xi, 106 pages
Copyright © 2016 Emily White
White, Emily. "Geospatial boundary dynamics." PhD (Doctor of Philosophy) thesis, University of Iowa, 2016.