基于水体季相差异的稻虾共作提取方法研究

STUDY ON EXTRACTION METHOD OF RICE-CRAYFISH BASED ON SEASONAL DIFFERENCE OF WATER

[目的]稻虾共作因为其较高的经济效益和生态效益,近年来种养面积呈持续增长态势。如何准确获取稻虾共作的面积信息与空间分布是当前研究亟待解决的问题。[方法]文章以湖北省潜江市为研究区域,首先根据稻虾共作模式独特的水域变化特征,利用自动水域提取指数(AWEIsh)分别获取不同季节的水体;然后基于水体季相差异提取稻虾共作农田的空间分布。该研究利用Landsat 8 OLI影像提取2017年潜江市的稻虾共作空间分布。[结果] 2017年潜江市稻虾共作主要分布在白鹭湖管理区、运粮湖管理区、熊口镇和龙湾镇等区域,和实际分布情况相吻合。在验证样本的基础上,通过混淆矩阵计算提取结果的精度可达到85. 01%。与改进的归一化差异水体指数(MNDWI)的提取结果相比,基于AWEIsh水体季相差异提取的结果精度更高:稻虾共作农田完整性好,错分情况少。[结论]基于水体季相差异的稻虾共作提取方法具有较好的提取效果,为今后研究提供了有效的技术手段。

Due to the high economic and ecological benefits,rice-crayfish pattern has developed rapidly in recent years. How to accurately obtain the area information and spatial distribution of rice-crayfish is an urgent issue to be solved in current research. The research took Qianjiang city of Hubei province as the research region. According to the unique water change characteristics of rice-crayfish pattern,the water of different seasons were obtained by automatic water extraction index AWEIsh. Then the spatial distribution of rice-crayfish was extracted on the basis of seasonal difference of water. And by utilizing such method,the spatial distribution of rice-crayfish in Qianjiang city in 2017 was extracted from the Landsat 8 OLI image. In 2017,the rice-crayfish farmland in Qianjiang city are mainly distributed in the Bailu Lake Management region,Yunliang Lake Management region,Xiongkou Town and Longwan Town,which are consistent with the actual distribution. Building on validation samples,the error matrix was used to assess the result. The accuracy of the extraction result reaches 85. 01%,which is much higher than the result obtained by modified of normalized difference water index MNDWI. Aiming to analyze the details of extraction results by AWEIshand MNDWI,the Bailu Lake Management Area with concentrated distribution of rice-crayfish farmland was taken as a typical region. The result of the AWEIshoutperform MNDWI: the rice-crayfish farmland with good integrity and less misclassification. The extraction method of rice-crayfish based on the seasonal difference of water body has a good extraction performance,which provides an effective technical mean for future research.