四类全球土地覆盖数据在中国区域的精度评价

    Accuracy assessment of four global land cover datasets in China

    • 摘要: 该研究以中国耕地类别为研究对象,选择2000年中国土地利用数据(NLCD-2000)为参考数据,利用比较分析法,从面积数量精度和空间位置精度两方面对目前4类全球土地覆盖数据(UMD、IGBP-DISCover、MODIS和GLC2000)产品进行了精度验证,并分析研究了4类数据精度的异同性。结果表明,4类全球数据对中国耕地数量特征和空间位置特征的估测具有明显的区域差异性。MODIS数据集和GLC2000数据集对中国耕地制图的总体精度要高于UMD数据集和IGBP-DISCover数据集。4类数据制图精度高的区域主要分布在中国的农业主产区,而误差大的区域主要分布在中国山区或耕地比例低的区域。低空间分辨率的信息源、基于像元的分类方法,以及中国复杂地形特征是4类全球土地覆盖数据精度差异的主要原因。

       

      Abstract: This study aims to examine the suitability of four global land cover datasets (UMD, IGBP-DISCover, MODIS and GLC2000) for their accuracies in mapping and monitoring cropland across China. For that, four global land cover products were firstly compared with the national land cover dataset 2000 (NLCD-2000) at provincial, regional and national scales to evaluate the accuracies of estimation of aggregated cropland area in China. This was followed by a spatial comparison to assess their accuracies in estimating the spatial distribution of cropland across China. The results showed that there were varying levels of apparent discrepancies in estimating China’s cropland among these four global datasets, and that both aggregated areas and spatial agreement between them varied from region to region. MODIS and GLC2000 datasets had a relatively higher accuracy in depicting China’s cropland than UMD and IGBP-DISCover datasets. The coarse spatial resolution and per pixel classification approach, as well as landscape heterogeneity, are the main reasons for large discrepancies between these four global land cover datasets and NLCD-2000 dataset.

       

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