Improving Spatial Data Quality through Spatial ETL Processes

Introduction

Current advances in technology and information systems and new initiatives, e.g., creating Spatial Data Infrastructures (SDIs), open the possibility to publish and share spatial (or geographic) and conventional data among interested parties. A SDI is defined as “the technology, policies, standards, human resources, and related activities necessary to acquire, process, distribute, use, maintain, and preserve spatial data” (OMB, 2010). These spatial data repositories distributed over the Internet at national or global levels mainly represent public sector agencies that could play both roles: data providers and consumers (Granell, Gould, Manso, & Bernabé, 2009; Elwood, 2008). SDIs’ purpose is to serve as a foundation for an Information Society willing to use and share spatial data over the Internet that “allow nations to better address social, economic, and environmental issues” (GSDI, 2012).

SDIs and other kinds of spatial data repositories over the Internet, e.g., Google Maps, Microsoft Bing Maps, make data available to different kinds of users. This data may form part of different Business Intelligence (BI) solutions (Bédard, 2005; Intelli3, 2010; Badard & Dubé, 2009; Bimonte, Wehrle, Tchounikine, & Miquel, 2006; Di Martino, Bimonte, Berttolotto, & Ferrucci, 2009) and the so-called location intelligence is mentioned as an important trend for the next-generation BI (Mathew, 2012). Spatially-enhanced BI solutions can help improve the decisions made at the personal, local, national, or global levels, due to the fact that, as it is widely acknowledged, the presentation of data within a space helps discover patterns that otherwise would be difficult to find. For example, on a personal level, a user could determine if the land that s/he wants to buy is not close to a garbage disposal or high tension towers, or whether the area is over-populated; on a local level, municipalities could rely on this data to prepare plans for cantonal human development in order to improve living conditions and strengthen territorial planning, or business managers could evaluate the distribution of customers that generate more profit; on a national level, authorities could make better decisions to create risk prevention plans for hazardous areas (e.g., flooding, erosion, earthquake) taking into consideration population, house distribution, or road availability, or business executives could analyze performance data related to a specific business field.

Nevertheless, several issues must be addressed before considering spatial data as “first-class citizens” in the decision-making processes at different levels of management. Traditionally, spatial data was stored in a central repository in a specific format provided by software tools developed for Geographic Information Systems (GISs). This software was perceived as a standalone technology until mid-1990s and was used mainly by experts in the field, i.e., geo-specialists, e.g., geographers, cartographers, surveyors (Yeung & Hall, 2007). This limitation was imposed due to the complexity of tools that manage spatial data and the necessary specialized knowledge (geo-knowledge) required to understand the concepts related to spatial data format, as well as functions and operations. These geo-specialists were mainly in charge of digitalizing spatial data and they understood very well the particularities of spatial data and problems that may affect its quality. Furthermore, they were aware that GISs will not help them improve spatial data quality since these systems work under the assumption that data is perfect and do not provide the capabilities to establish data quality control (Delavar & Devillers, 2010). Although, spatial DBMSs (called geo-databases by geo-specialists) currently provide some controls, e.g., declarative and dynamic (triggers), that may help improve spatial data quality, the transition from the traditional storage of spatial data to a new alternative requires geo-specialists to acquire new knowledge that is not always an easy and time-efficient endeavor.