Exploring Potential Human Activities in Physical and Virtual Spaces: A Spatio-temporal temporal GIS Approach

Transcription

1 Exploring Potential Human Activities in Physical and Virtual Spaces: A Spatio-temporal temporal GIS Approach Hongbo Yu Department of Geography, The University of Tennessee Knoxville, TN , USA yuhongbo@utk.edu

2 Introduction Physical presence vs. tele-presence Information and communication technologies (ICT) have enabled a virtual. People can participate in activities and interact with others remotely through tele-presence instead of physical presence. Time geography (Hägerstrand, 1970) It provides a useful framework to study spatial and temporal aspects of individuals activities. Activities in the virtual are not well addressed. Limited progress is made to develop a GIS-based operational system. The main objective of this research is to develop an operational geographic GIS for representation, analysis, and visualization of human activities in physical and virtual s.

3 Time Geography Hägerstrand (1970) proposed a framework to study the relationships between various constraints and human activities in a - context. Three key concepts: - path (ST path) - prism (ST prism) potential path area (PPA) Space-Time Path t2 Space-Time Prism t1 Potential Path Area

4 A Conceptual Model for Physical and Virtual Spaces Physical and virtual have different rules to control activities within their domains. In the mean, the two s also intersect with each other. The physical provides access channels to the virtual. The virtual feeds back information to impact individuals activities and travel patterns in the physical. physical Navigation mode: transportation access channels intersection information flows virtual Navigation mode: ICT

5 Space- Prisms for Virtual Activities t2 t2 Internet port t1 t1 Cellular phone service area ST Prism for wired access ST Prism for wireless access

6 Four Types of Communication Modes Four types of communication modes have been identified based on their spatial and temporal characteristics (Janelle, 1995; Harvey and Macnab, 2000; Miller, 2003). Temporal Spatial Physical presence Synchronous SP (co-existence) Face-to-face meeting Asynchronous AP (co-location in ) Fridge note Traditional hospital charts Telepresence ST (co-location in ) Telephone Online chat rooms AT (no co-location in either or ) Web pages (Adapted from Miller, 2003)

7 Spatio-temporal temporal Relationships of Prisms and Potential Human Interactions t 2 t 1 t 22 initiator receiver t 21 t 12 t 11 l 1 l 2 Potential SP interactions l 1 l 2 Potential AP interactions initiator receiver t 2 t 1 t l 11 l 12 l 21 l 22 Potential ST interactions l 11 l 12 l 21 l 22 Potential AT interactions

8 Incorporating Time-geographic Concepts in GIS Miller (1991) first brought - prism concept into GIS and implemented network-based potential path areas (PPA). Recently, additional efforts have been made to apply geographic concepts in GIS (e.g., Kwan and Hong, 1998; Miller 1999; Miller and Wu, 2000; Weber and Kwan, 2002; Kim and Kwan, 2003; Weber 2003). Representation of - paths and prisms in GIS remains a research challenge (Yuan et al., 2004), especially for situations of handling both physical and virtual s and analysis of interactions among individuals.

9 A Spatio-temporal temporal GIS Design for the Extended Time-Geographic Framework Three-dimensional spatio-temporal features: 2D + 1D Spatio-temporal point feature Spatio-temporal line feature (x 6, y 6, t 6 ) Spatio-temporal 3D feature t 2 (x, y, t) (x 5, y 5, t 5 ) t (x 4, y 4, t 4 ) t 1 (x 2, y 2, t 2 ) (x 3, y 3, t 3 ) (x, y) (x 1, y 1, t 1 )

10 An Explicit Representation of Space- Prisms Forward cone/backward cone: the boundary of a prism Represented as a set of spatio-temporal line features Prism Represented as a collection of vertical spatio-temporal line features, which indicate activity opportunities at various locations with explicit information. prism backward cone forward cone

11

12 Network based - prisms forward cone backward cone Space- prism Potential path area Origin Destination

13 Space- life lines for wired access Space- life cylinders for wireless access Extended - prism with wired access Extended - prism with wireless access

14 2005 AAG Annual Meeting Denver receiver initiator A case for potential SP interactions A case for potential AP interactions receiver A case for potential ST interactions initiator A case for potential AT interactions

15 Summary Contributions of this study: Extends - prism concept to represent potential human activities in both physical and virtual s; Develops a spatio-temporal GIS design to accommodate the extended concept by providing functions to compute and visualize - prisms in a 3D GIS environment and to support analysis of spatio-temporal relationships among individuals; and Offers an effective approach of dealing with spatio-temporal, individual activity data in a GIS environment.