Environmental Monitoring System Based on GIS and Wireless Communications Ming Huang Surveying and Mapping Engineering Department Heilongjiang Insitute technology Harbin, China kyshm126.com Yinbin Wu Department of Business Administration Hebei Economic and Trade University Shijiazhuang, China wuyanbin080126.com Abstract To solve the problems in environmental monitoring arising from remote data acquisition, real-time transmission and analysis, this paper researched the principle of wireless communications SMS / GPRS and the technology of seamless integration with GIS. The system architecture was designed and key technical solutions were implemented. Based on the SMS / GPRS technology, the wireless real-time transmission of the remote monitoring data was achieved, and GIS visualization technology was carried out to visualize the monitoring data. Geographic affected areas were analyzed by GIS spatial analysis. The system is applicable to the environmental protection departments to realize applications such as monitor data acquisition, communication transmission, GIS management and analysis and decision-making. Environmental;Monitoring;Wireless communications;Geographic Information System;Spatial Analysis I. INTRODUCTION Along with the development of society, the environmental protection industries put forward higher request to environmental monitoring, mainly embodies in real-time dynamic monitoring data collection, dynamic tracking and management, dynamic analysis and visualization, and so on1. In recent years, SMS, GPRS wireless communication technology has been applied to the environmental monitoring areas to solve the problem of remote data acquisition and transmission 2-6. In the environmental monitoring and management, GIS technology has been used to achieve environmental monitoring information visualization analysis and prediction 7-9. II. SYSTEM THEORY The terminal equipment of Environmental monitoring stations whether use which kinds of communication, must have function of pollution factor data collection and wireless data transmission launch. The data acquisition module and data transmission module were connected mainly through RS232, and wireless transmission was processed by short messages and GPRS. A. SMS Principle SMS message service based on GSM mobile network is a wireless application to send short message and it is a information process of storage and forward on the mobile network. The information send out from the sender is stored in the short message center (SMSC), and then is forwarded to the user terminals. The standard protocol is short message SMPP.Short message communication process as follows. Terminal launch short messages (MO Process). MO after GSM network to short SMSC information center. Information received by short message center is transmitted to the corresponding gateway CMPP or other gateway. CMPP through the Internet gateway transmit the original message launched by terminal server to SP operation. SP operation server process data and the data processed back to gateway by the Internet (MT Process). Gateway sends data to SMS again, and through the GSM to send message to user terminals. The environmental monitoring system is on the SP operation server, and then, in this system data acquisition device has function of short message transceiver as well as environmental monitoring data collection. B. Communication Principle GPRS communication is based on data packet communications network which is through IP address. The mainframe computer in monitoring center is configured by fixed IP address, GPRS modules or devices are used to connect collect data and the mainframe computer. The communication process is like a computer in a network of computers via TCP/IP SOCK communication. Data of pollution information automatic acquired by data acquisition module at environmental monitoring points are connected to GPRS transparent data terminals through RS232 interface and by GPRS transparent data terminal built-in embedded processors are processed and packaged late-development to GSM network protocol, and then, by GGSN (Gateway GPRS Support Node) wireless network to be China National Natural Science Foundation (#40672104) China National Program on Key Basic Research Project (#2006CB202209 and 2005CB221500) 978-1-4244-4713-8/10/$25.00 2010 IEEEFire Wall地地地地MCCDDN /ISDN/E1LinkInternetPollution SourceRTUsIMCGIS EMIMBusiness Processing Center ? transmitted and, eventually, reach the monitoring center IP address. III. SYSTEM STRUCTURE This environment monitoring system is shown in figure 1, the system is divided into three parts: Figure 1. Structure of the system RTUs (Remote Unit RTU) are distribution in different regions which have integrated data collectors and GPRS or SMS Terminal equipments. Data collectors can acquire various environmental parameters (wastewater, waste gas, dust, noise) on the real time. GPRS or SMS equipment through RS232 interface sent data acquired by collectors to wireless public network based on GSM. Data send by GPRS or SMS terminals are communicated to MSC (Mobile Switching Center by wireless network, again by GGSN or SGIP or CMPP or CNPP gateway, cabled to monitor communication Center. Cable connections include straight line (DDN, E1) and ADSL and Internet connection. On the view of information security the Internet and ADSL are connected to the monitoring center through a firewall filtering. Monitor communications center(MCC) is mainly responsible for handling GPRS data packets and SMS packets, and for the database server data into operation, it also for radio communication SOCK to each subsystem. IV. SYSTEM REQUIREMENTS System mainly consists of three modules: monitor communication center, information center and GIS environment monitoring information management. A. Monitor CommunicationCenter(MCC) Monitor communications center is mainly responsible for handling the terminals of the short message data or launched packets through GSM or GPRS wireless transmission to the corresponding mobile gateway, and then, gateway through DDN, E1, ISDN cable connection transmit the packet to monitor communication center. The monitoring center receives packets for analytical processing (including protocol data and remote monitoring of environmental equipment acquisition system parameters). Monitor communications center adopts multithreaded programming technology, receiving and analytical data packets real-time information, and then write to the database server received information. Figure 2. Spatial analysis of pollution sources B. Information Management Center(IMC) Information management center function mainly includes: Terminals information data entry, modification. Equipment information includes equipment models, SIM card short message center, special services based on SMS communication; Logon DSC Password; DTU Communication Port; Mobile Service Center (MSC) Service Code. User management, including add, delete, modify user, different roles are divided according to the business logic levels, so different user permissions have different views and operation of the data. Environmental protection agency information management. Enterprise information management mainly reflects the subordinate environmental supervision brigade, business scale, equipment installation, the main pollutants. Management of pollutants, classification, name of pollutants, warning threshold level alarm and etc. C. GIS Environment Monitoring Information Managemen(GIS EMIM) Based on GIS environment monitoring is the core of the system, it is built in commercial Oracle9i database through MapX component technology, using integrated secondary development. Through the GIS visualization technology system can visualize remote monitoring equipment transmission of data acquisition, when pollution index is overweight it show alarm information, and then highlight on the map. Besides system also combining GIS spatial analysis analizes pollution area, provide the scientific method for the governments macro decision. Main features include: Map storage.Map using Oracle9i Object Relational Model to manage the geographic data storage, client use MapX5.0 data access requests, therefore system analysis and satisfy the mass of data management and multiple user data sharing and real-time concurrent processing. Map operation and editing.Map realize stepless zoom, roaming and reset operation, and through the eagle eye location. Data query.Click on the map layer of dot, line, face the elements can popup list, it based on the attribute information can also quickly locate geographic entities directly. The equipments pickde by the mouse directly show the key information such as SIM card, monitor alarm threshold, monitoring the variety of pollutants. System offers a variety of interactive selection method, rectangle, polygon area, circle choose etc. Space analysis.Space analysis is the key of environmental monitoring information management. Space analysis mainly is to select the suitable diffusion model, such as the dot, line, non-point source diffusion mode, and establish the pollution sources of regional influence. Figure 2 shows a plant by gauss diffusion model of contaminated area. Combined with the pollution diffusion model this spatial analysis method is more practical application value than traditional simple given radius parameter analysis in GIS. Forecasting and analysis.According to the historical environment monitoring data, using the regression analysis method, the exponential smoothing method and grey forecasting method, neural networks method can predict a regional environmental quality trend and combining GIS visualization technology in the map shows prediction results10. Statistics and output.Statistics of the administrative division monitoring equipment, as well as daily, weekly, monthly, quarterly and annual statistical data, and the monitoring results in geographical map can be showed, and then generate the pie chart, histogram, etc. V. REALIZATION OF SOFTWARE SYSTEM The overall design system in fully reflects the GIS, wireless transmission, environment monitoring seamless integration of the three modules. Development language is Visual Studio2005 VC.NET comprehensive use of MFC and CRL and Oracle9i database is adapted to integratedly access attribute data and the of spatial data, using MapX component to implement map visualization display and spatial geographical analysis. A. Software Architecture Key technologies of the system software are below two aspects: Wireless data real-time transmission and communication center of packets of decoding. The cooperation between modules Figure 3 shows the software structure.Software is divided into three tiers, namely, the core-tier, Middle-tier, and application-tier. In order to ensure the whole system work together between each layer via TCP/IP protocol is used for packet distribution. GIS engine based on MapX in the core-tier is responsible for customer request response of map and space analysis. Because Oracle9i using object-oriented database containing a relational attribute database and spatial data, its access mechanism is more complex. Therefore, the system make encapsulation of database access, so database access are processed by database gateway, instead of directly on the database access, only database gateway to directly facing the underlying database. The middle-tier is the core services dispatch which is automatically packet distribution. Application-tier included wireless communication (SMS and GPRS), based information management, GIS application and other application module. Application layer is logic business, but not know Oracle9i space database and attribute database, simply manipulate technical details to the core of service dispatching tasks, sending requests or core services with GIS database request. Figure 3. Software structure B. Realization of communication processing software Communication processing includes the TCP/IP communications of SMS, GPRS and software system structure. The message for system structure is simple, and can be directly through the Sock. Based on the wireless communication and using multithreading software realization is introduced, its core threads are as follows: void Thread_Connect(LPVOID param) Core Services Dispatch Database Getway Map Engine MapXGIS Engine GIS of ApplicationManagement Information Base Other Application SMS GPRS wireless telecommunicationsApplication-tier Middle-tierCore-tierAattribute DataSpatial DataOracle 9i According to the remote gateway IP and port, the TCP/IP protocol physical links. void Thread_TCPSendAuth(LPVOID param) After successful physical links, user name and password authentication binding, need MD5 encryption. void Thread_SendAlive(LPVOID param) To ensure the link links to send every time, when the link test kit to link failures, start Thread_Connect and Thread_TCPSendAuth, so as to realize the link links unattended. void Thread_MsgNotify(LPVOID param)； Receiving the message thread which core are Deliver messages. C. GIS engine In this system, the purpose of GIS integration is to let the real-time monitoring data visual expression on the map. Combining with the GIS spatial analysis function the influence sources of radiation radius can be analyzed. The key steps are as follows: 1) Map data loading Data layer mainly includes monitoring equipment, residential, industrial and mining roads, water and other features, through the EasyLoader tool in MapInfo upload the map data to Oracle9i database server, thus map of spatial data and attribute data are in integration storage. 2) Login Oracle9i spatial database server In this system MapX due to the use of Oracle9i database, it is different from directly loading Tab document, needs to use CMapXLayerInfo class, such as: a) Class instantiation CMapXLayerInfo layerInfoObject;LayerInfoObject.CreateDispatch(layerInfoObject. GetClsid(); b) Specifies data from a database,layerInfoObject.SetType(miLayerInfoTypeServer). c) Call AddParameter database connection string, the method of database table Settings. d) Add the MapX control to this layer and display: m_ctrlMapX.GetLayers().Add(layerInfoObject,1). 3) Space analysis Spatial analysis mainly involves the following spatial operator in Oracle9i: a) Space objects not judge:SDO_FILTER and SDO_RELATE b) Specified object search within a certain range:SDO_WITHIN_DISTANCE c) Buffer analysis:SDO_BUFFER d) Adjacent retrieval:SDO_NN VI. ACKNOWLEDGMENT This research is supported by China National Natural Science Foundation (grant #40672104) and the China National Program on Key Basic Research Project (grant #2006CB202209 and 2005CB221500). VII. CONCLUSION SMS and GPRS wireless communication technology solve the environmental monitoring equipment remote data transmission on real-time. Through the multi-thread programming method, automatic detection and communications link have been realized. System based on object relational database Oracle9i realized the GIS spatial data and attributes integration of storage, by using the GIS technology data collection are visual displayed, applyed space analysis function of GIS to complete the pollution diffusion and influence of visual analysis area. The communication construction used TCP/IP protocol, through the core of service dispatching module to handle each module of the whole system, realized the collaborative work, the more module and effective integration of GIS and SMS/GPR communications technology. 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