GVG农情采样系统及其应用

GVG, a Crop Type Proportion Sampling Instrument

介绍了通过对GPS、VIDEO摄像头、GIS的综合集成 ,用于野外农作物采样的信息快速采集、定位和处理分析系统 ,简称为GVG农情采样系统。系统包括影像采集卡、视频摄像头、GPS接收卡、GPS天线和工控计算机 ,在野外采集时采用汽车为主要工作平台 ,以各级公路为样线进行动态采样。系统工作时实时采集GPS信号 ,捕捉视频影像 ,同时根据GPS位置自动获得GIS属性信息 ,并自动记录在后台数据库。野外工作结束后 ,系统提供的功能允许操作人员对每条记录的照片中各类农作物所占比例进行赋值 ,统计单元内各种作物的分类成数 ,包括采样线、县级、农业区划级和省级单元。GVG系统的自动数据采集方式和GIS支持下的图像分析和统计方法提高了数据的采集和室内数据分析的效率 ,同时保证了采样的精度 ,经过不同地区的精度检验 ,作为“中国农情遥感监测系统”的重要组成部分 ,在全国范围内对大宗农作物分类成数的监测精度达到 95 %以上。

GVG instrument is an integration of video capture card,GPS receiver and GIS for collecting the crop type proportions in the field. VIDEO and GPS are integrated into the GIS installed in a notebook. GVG mounted on car or motor takes records with video camera during the movement. The car should not be fast than 40 km/h in order to acquire high quality of pictures. When GVG is working, it records pictures and the position from GPS as well as geographical attributes from GIS data layer, for example county code, into a temporarily database. One person is enough to operate GVG in addition the driver. When fieldwork is done, the GVG provides the function to review every pictures recorded during the sampling. If the picture does not contain the arable land, it shall be discarded, otherwise, the proportion of every crop types will be recorded manually, and the picture will be recorded too. Once all pictures are reviewed for a transect line, it is easy to calculate the proportion of crop types. The crop proportions for a county can be calculated from all transect lines within the county, and the same for stratum. GVG has been used to obtain the crop type proportions of entire country since 1999. The extensive validation shows the GVG can have the accuracy of 95% for main crops, including wheat, rice, maize and soybean. According to the principle of GVG, it has multi-purpose applications, not only on the crop type proportions, but also on environment monitoring for example.