A visual query language for GIS.
详细信息
文摘
The primary goal of this work is to investigate the integration of exploratory geodata handling (EDH) in Geographic Information Systems (GIS), which traditionally provides only operational geodata handling (ODH) functionalities. ODH in this context refers to day-to-day operations such as data collection, cleaning, management, retrieval, inductive-statistics, and simple presentation. EDH on the other hand includes numerical exploratory data analysis and visualization. The inspiration behind this work is that conventional GIS does not provide the necessary means for the effective discovery of new knowledge or hidden patterns from vast amount of existing geographic data. Furthermore, existing third-party data mining tools cannot effectively explore geodata due to the intrinsic characteristics of spatiotemporal phenomena such as spatial/temporal autocorrelation, and the general complexity of geodata. It is suggested here that a viable solution is to devise a new type of GIS that supports both ODH and EDH in an integrated environment.;To realize this ODH-EDH integration in GIS, this work is developed along two threads. In the first thread I develop a conceptual data model that is generic and flexible for modeling both ODH and EDH operations. More specifically, a set-based conceptual model called Geoset is developed, along with a comprehensive taxonomy of geospatial operations. The taxonomy organizes various operations of ODH and EDH operations on a conceptual level rather than implementation level.;In the second thread of my work, I develop a visual query interface which brings the conceptual uniformity of ODH/EDH to end users, through a consistent and diagrammatic programming metaphor. This visual user interface shields the user from the horrendous complexity of working directly with both exploratory data analysis and operational geographic data processing. A prototype implementation for this visual query language is described in this work.;In summary, this work provides both theoretical and practical means for developing future geographic information systems that support ODH and EDH operations in a single environment.