基于工作流的TVDI网络服务设计与实现

基于植被指数和地表温度计算得到的温度植被干旱指数(TVDI)能够较好的反映土壤干湿情况,是土壤湿度检测的重要指标。现有的TVDI计算的实现是针对特定的遥感数据,采用了不同的编程语言和运算环境,当出现新的算法和遥感数据时,就需对TVDI计算进行重新编码,因此不能很好的借助已有的信息资源。其次土壤信息本身内容繁杂,尤其在进行海量时序数据分析时,不可能在一台计算机上进行全部的信息处理。因此研究网络环境下可重用的土壤信息处理是十分必要的。Web Service是网络环境下的信息共享的基础,工作流技术能够很好的对Web Service信息进行组合。以Windows Workflow Foundation为工作流建模语言,以武汉地区为例,建立了通用的TVDI计算工作流模型。讨论了在保持原有的TVDI计算工作流模型不变情况下,对不同空间分辨率情况下TVDI工作流模型进行更新,实现了TVDI计算服务的共享。采用工作流实现TVDI计算能够发挥Web Service在网络环境中的作用,提高现有处理服务资源的利用率。

TVDI Web Service Design and Implementation Based on Workflow Technology

Temperature-vegetation dryness index(TVDI) is calculated in describing the soil moisture,based on the vegetation index(VI) and land surface temperature(LST).Available TVDI calculation depends on the remote sensing data and computational algorithms.So the algorithms and remote sensing data updating causes the duplicate implementation of the TVDI calculation,which contains repetition and can’t use the available information resources.Soil information content is mass,miscellaneous and toilsome.Especially in the sequential analysis,it is impossible to process all the information in only one computer.So it is necessary to research on the soil information reusing in the internet environment.Web Service technology is the foundation for sharing the information on the internet,and the workflow technology used for combining with the Web Service resources.In this paper,all research work was based on the Web Service and workflow technologies and the Windows workflow foundation model was used as the modeling language.Taking Wuhan as a study area,the TVDI calculating workflow model was built up and all the related algorithms implementation was based on the Matlab and ArcEngine.Then,the article discussed how to update the TVDI workflow model to fit the different spatial resolution remote sensing images,at the same time keep the original TVDI calculation workflow model and avoid the duplicated working.Therefore,to take the workflow model as a resource organizing and sharing method could provide an efficient way to use available resources by taking the advantage of the workflow.