Spatio-temporal Environmental Monitoring Systems : A data management and delivery approach based on PostGIS database and Google Maps mashup
A considerable amount of data, including spatial data referring to monitoring locations together with their related attribute time series (as in, for example, rainfall or contaminant concentrations), is usually collected and/or generated by environmental monitoring networks. In such a scenario, proper spatio-temporal management and data presentation strategies play a crucial role in minimizing duplication and integrity failure risks and in ensuring an efficient access to environmental data for visualization, analysis and modelling purposes. The current paper investigates an open-source spatio-temporal multi-user concurrent database strategy, based on PostGIS and its implementation of table inheritance, and suggests a new conceptual and operative framework within which to address some fundamental issues in surface waters and groundwater domains. This is done by also acknowledging and complementing some general ideas already available and developed by ESRI-CRWR’s leading hydro and groundwater hydro models. A geoweb data presentation strategy based on a Google Maps API v.3 mashup, mainly grounded on PostGIS database as a backend and Google Flash widgets for time-dimension navigation, is then considered. Several advantages deriving from the proposed approach in exploratory spatial data analysis are discussed and an example focused on spatio-temporal visualization in a multi-years groundwater monitoring project is briefly discussed. Despite state-of-the-art spatial database and GIS systems already support a full set of powerful and advanced features, authors point at those organizational difficulties and financial constraints arising from the decision of relying on mostly proprietary systems, which often limit the pursuing of proper and yet simple environmental data management and delivery policies and practices, and –by contrast- end up favouring the adoption of poorly structured approaches, by even leading to Excel or shape-file syndromes. Whilst the proposed solution still demands for advanced competencies at design and development stages, the paper emphasizes how users can strongly benefit from a seamless integration of web applications with spatial databases, which would provide a highly interactive and user-friendly experience in accessing and investigating spatial data and related attribute time series.