摘要:
油菜是我国主要的食用油料作物.及时、准确地获取油菜种植分布信息对油菜长势监测、估产以及灾情评估具有十分重要的意义.以江汉平原为研究区,利用250 m空间分辨率的MODIS EVI时序数据,以TM数据作为野外采样数据与MODIS EVI数据之间的过渡数据,间接提取MODIS EVI数据农作物的训练样本;通过分析江汉平原油菜和冬小麦的EVI光谱特征及物候信息,建立油菜种植面积提取模型;采用多次阈值比较法提取2014—2015年间江汉平原油菜种植分布信息.研究结果表明,2014年和2015年油菜面积遥感提取结果与农业局统计数据相比,总体提取精度分别达到95.22%和91.29%;2014年MODIS数据与TM数据提取的油菜面积一致性为88.61%;基于时间序列MODIS EVI数据,结合EVI光谱特征和物候信息,利用该方法可以有效提取江汉平原油菜种植分布信息.
Abstract:
Rape is the major oil crop in China, and timely and accurately obtaining the information about rape planting spatial pattern has great significance for growth monitoring, yield estimation and disaster assessment. In this paper,the distribution of rape growing in the Jianghan Plain from 2014 to 2015 was extracted utilizing the MODIS EVI time series data with 250 m spatial resolution. The field survey data were used to extract crop training samples for MODIS EVI data indirectly by using TM data as the transition data between the field survey data and MODIS EVI image. According to the spectra and phenological calendar of winter wheat and rape in Jianghan Plain, the authors established the extraction model for the area of rape growing by multiple threshold comparative method. With the Agricultural Bureau Statistics data as the verification, the overall accuracy of the extraction results of MODIS data were up to 95.22% and 91.29% respectively in 2014 and 2015. In addition,the extraction result was quite consistent with TM-based result with a precision of 88.61%,in 2014. The results show that,based on the time series MODIS-EVI data sets,combined with the EVI spectral characteristics and phenological information of crop and using the study method presented in this paper, the rape planting distribution information could be extracted effectively in Jianghan Plain.
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