WebGIS在农业环境物联网监测系统中的设计与实现

Design and implementation of monitoring system for agricultural environment based on WebGIS with Internet of Things

近年来物联网技术在农业环境监测领域得到了广泛的应用。物联网能够及时获取监测点上时间连续的数据,但在进行较大尺度的区域监测时,因空间变异性影响,基于节点的物联网监测技术面临着监测点分布设计、数据空间连续表达等诸多难题。针对农业环境监测对象的特点,提出了由点到面的区域模拟与评估方法,设计了一套将物联网基于"点"的监测数据与WebGIS基于"面"的空间数据融合分析的解决方案。在已建立的物联网监控中心系统平台基础上,优化集成WebGIS图形化空间分析技术,建立了物联网监测数据与WebGIS空间数据点面融合的农业环境监测系统。系统实现了数据位置地图显示、由点到面的区域模拟与评估、区域监测专题图管理3个功能。以河南省小麦灾情监测为案例对系统进行了应用分析,结果表明系统能有效地实现农业环境由点到面的区域动态监测,提高了作物长势与灾害的综合诊断能力,并能够为农业生产管理提供更为便捷的应用服务。

There are two of the main practical monitoring approaches in agriculture including remote-sensing monitoring and on-farm monitoring. Remote-sensing monitoring uses remote-sensing technologies and devices such as satellites and aerial vehicles to extract the key parameters of agricultural information. The remote-sensing technology is effective on regional-scale monitoring, but difficult to collect real-time information in farmlands. On-farm monitoring uses a variety of sensors deployed in farmlands as well as corresponding data processing and transmission equipment to dynamically acquire on-farm information. The Internet of Things （IoT） technology based on the sensor nodes has been widely used in the field of agricultural environment monitoring in recent years. However, when a regional-scale monitoring is carried out by using the IoT technology, there are some problems in the distribution of monitoring sites and the space representation of monitoring data. Aiming at the problems, an approach to evaluation of agricultural environment from on-farm sites to regional scales and the corresponding solution are proposed in this paper. Most of the factors of agricultural environment remain minor variation and appear to be uniform in the same ecological type region, except for extreme weather events or geographical conditions. Therefore, the agricultural environmental information acquired by an on-farm monitoring site could be regarded as the representation of the entire farm where the site located, and the agricultural environmental information of a representative farm could be also considered as the reflection of an entire ecological type region with similar geographical and environmental conditions. An IoT-based monitoring system has been put into application in the past five years which includes a total of 110 on-farm monitoring sites in representative regions of wheat belts across 14 provinces of China and a central monitoring platform. Based on the established central monitoring platform, a regional-scale monitoring system for agricultural environment is designed by integrating with the spatial analysis technology of WebGIS. In the system, three types of WebGIS-based functions were implemented, including site data positioning, regional-scale evaluation, and thematic mapping. Through an interactive online map, positioning, real-time display and query of on-farm sites information and collected data are realized in the site data positioning. The regional-scale evaluation is used for analysis of the collected agricultural environmental information, and decision-making on crop growth conditions and meteorological disasters from on-farm sites to regional scales, while the thematic mapping is used for automatic generation, dynamic display and query of regional-scale monitoring thematic maps of crop growth conditions and meteorological disasters based on the evaluation. The fusion analysis of “on-farm” IoT data and “spatial” WebGIS data is provided in accordance with the characteristics of monitored objects. The system has been put into application in monitoring of wheat growth conditions and meteorological disasters in Henan Province. And the case is demonstrated in dynamic regional-scale monitoring of wheat dry-hot wind occurred on May 11, 2013 in Henan Province. The result indicates that the system is effective when monitoring agricultural environment from on-farm sites to regional scales with dynamical update and the applicability on diagnosis in crop growth conditions and meteorological disasters is improved.