Real-time Monitoring Portal for Urban Environment Using Sensor Web Technology

Taking advantage of the large-volume but low-cost datasets remotely sensed in urban areas by ubiquitous sensors or sensor networks, there is a need of real-time environmental monitoring portal or geospatial infrastructure for effectively or efficiently collecting and serving vast field data over web. Based on Open GIS Service Specifications defined by OGC Sensor Web Enablement (SWE), this paper presents an Internet based urban environment observation system that can real-time monitor environmental changes of temperature, humidity, illumination or air components in urban area. This system two functionality components. One is to collect and archive the environmental data from low-cost sensor network with user-customized time frequency through the proprietary system interfaces, the other is to support those datasets to be reformatted following Earth Observation (EO) specification and to be browsed or retrieved through the open interoperation interface of Sensor Observation Service (SOS). The real-time monitoring system is developed using Open GIS Specifications and Open Source Geospatial Software. The test-bed system is demonstrated as follows. The sensor kit deployed for constructing environmental monitoring network refers to the hardware implementation by GIS Research Group of OCU under Prof. Venkatesh. Currently, the factors of temperature, humidity, carbon dioxide and oxygen are sensed through outdoor sensors. The sensor data archive database is established using PostgreSQL and PostGIS platform and the web service system is run over Apache server. The data collection service and sensor data web service are programmed using Python, while the data visualization services are implemented using OpenLayers and Mapserver.