草业学报 ›› 2025, Vol. 34 ›› Issue (2): 149-162.DOI: 10.11686/cyxb2024110
• 研究论文 • 上一篇
麦晶晶1(), 冯琦胜1(), 王瑞泾2, 封森耀3, 金哲人4, 张忠雪1, 梁天刚1, 金加明5
收稿日期:
2024-04-09
修回日期:
2024-06-20
出版日期:
2025-02-20
发布日期:
2024-11-27
通讯作者:
冯琦胜
作者简介:
E-mail: fengqsh@lzu.edu.cn基金资助:
Jing-jing MAI1(), Qi-sheng FENG1(), Rui-jing WANG2, Sen-yao FENG3, Zhe-ren JIN4, Zhong-xue ZHANG1, Tian-gang LIANG1, Jia-ming JIN5
Received:
2024-04-09
Revised:
2024-06-20
Online:
2025-02-20
Published:
2024-11-27
Contact:
Qi-sheng FENG
摘要:
耕地是农业生产和保障粮食安全问题重要的物质基础,耕地的准确识别对耕地资源的保护和农业生产可持续发展有着重要意义。为了构建高精度的耕地识别模型,本研究基于空间云计算平台使用Sentinel-1/2数据,构建不同特征类型组合,通过特征重要性分析对耕地识别特征进行筛选,形成最优特征集合,使用随机森林(random forest,RF)、支持向量机(support vector machine,SVM)和分类回归树(classification and regression tree,CART)模型对甘肃省张掖市2021年度的耕地进行识别,同时对比分析了各分类器的分类精度。结果表明,使用植被指数特征、雷达特征和地形特征的特征类型组合能够把分类精度提升到91.32%;在研究区耕地识别中表现较好的特征有海拔(elevation)、雷达VH极化通道及归一化水指数(normalized difference water index, NDWI)等;在张掖市耕地识别中,RF算法优势明显,总精度达90.04%,Kappa系数为0.79,基于RF模型得到的张掖市耕地面积为58.5万hm2,面积占比为15.4%。本研究实现了张掖市耕地的精确识别,可为该地区耕地制图提供参考。
麦晶晶, 冯琦胜, 王瑞泾, 封森耀, 金哲人, 张忠雪, 梁天刚, 金加明. 基于机器学习的高精度耕地识别模型构建——以甘肃省张掖市为例[J]. 草业学报, 2025, 34(2): 149-162.
Jing-jing MAI, Qi-sheng FENG, Rui-jing WANG, Sen-yao FENG, Zhe-ren JIN, Zhong-xue ZHANG, Tian-gang LIANG, Jia-ming JIN. Construction of a high-precision cultivated land identification model based on machine learning-using Zhangye City, Gansu Province as an example[J]. Acta Prataculturae Sinica, 2025, 34(2): 149-162.
图1 研究区概况基于自然资源部标准地图服务网站甘S(2023)91号标准地图制作,底图边界无修改。The map was based on the standard map service website of the Ministry of Nature Resources with the drawing review No. gan S(2021)91, and the base map borders were not modified.
Fig.1 Overview of the study area
图2 研究区样本点分布基于自然资源部标准地图服务网站甘S(2023)60号标准地图制作,底图边界无修改。The map was based on the standard map service website of the Ministry of Nature Resources with the drawing review No.gan S(2023)60, and the base map borders were not modified.
Fig.2 Samples distribution of study area
图3 工作流程RF: 随机森林Random forest; SVM: 支持向量机Support vector machine; CART: 分类回归树Classification and regression tree; RFE: 递归特征消除Recursive feature elimination; Kappa: 卡帕系数.
Fig.3 Workflow of the cultivated land identification in Zhangye City
编号Number | 特征类型组合Feature type combinations |
---|---|
1 | 光谱Spectrum |
2 | 光谱+雷达Spectrum+synthetic aperture radar (SAR) |
3 | 光谱+植被指数Spectrum+vegetation index |
4 | 植被指数+雷达Vegetation index+SAR |
5 | 光谱+植被指数+雷达Spectrum+vegetation index+SAR |
6 | 植被指数+雷达+土壤Vegetation index+SAR+soil |
7 | 植被指数+雷达+地形Vegetation index+SAR+topography |
8 | 植被指数+雷达+地形+土壤Vegetation index+SAR+topography+soil |
9 | 全部特征类型组合All feature types |
表1 9组不同特征类型组合
Table 1 9 groups of different feature type combinations
编号Number | 特征类型组合Feature type combinations |
---|---|
1 | 光谱Spectrum |
2 | 光谱+雷达Spectrum+synthetic aperture radar (SAR) |
3 | 光谱+植被指数Spectrum+vegetation index |
4 | 植被指数+雷达Vegetation index+SAR |
5 | 光谱+植被指数+雷达Spectrum+vegetation index+SAR |
6 | 植被指数+雷达+土壤Vegetation index+SAR+soil |
7 | 植被指数+雷达+地形Vegetation index+SAR+topography |
8 | 植被指数+雷达+地形+土壤Vegetation index+SAR+topography+soil |
9 | 全部特征类型组合All feature types |
图4 9种特征类型组合的分类精度和Kappa系数比较图中特征类型组合1为光谱特征,组合2为光谱和雷达特征组合,组合3为光谱和植被指数的特征组合,组合4为植被指数和雷达的特征组合,组合5为光谱、植被指数及雷达的特征组合,组合6为植被指数、雷达及土壤的特征组合,组合7为植被指数、雷达及地形的特征组合,组合8为植被指数、雷达、地形及土壤的特征组合,组合9为全特征组合。The combinations of feature types in the figure are as follows: Combination 1 consists of spectral features; Combination 2 consists of a combination of spectral and synthetic aperture radar features; Combination 3 consists of a combination of spectral features and vegetation indices; Combination 4 consists of a combination of vegetation indices and synthetic aperture radar features; Combination 5 consists of a combination of spectral, vegetation indices, and synthetic aperture radar features; Combination 6 consists of a combination of vegetation indices, synthetic aperture radar features, and soil features; Combination 7 consists of a combination of vegetation indices, synthetic aperture radar features, and topography features; Combination 8 consists of a combination of vegetation indices, synthetic aperture radar features, topography features, and soil features; Combination 9 consists of all features.
Fig.4 Accuracy and Kappa coefficient comparison of 9 feature type combinations
识别特征Feature | 特征重要性Feature importance |
---|---|
海拔Elevation | 8771.81 |
VH, 雷达特征中的VH极化Synthetic aperture radar features VH polarization | 8210.86 |
归一化水指数Normalized difference water index, NDWI | 8128.18 |
简单比值Sample ratio, SR | 7979.18 |
VV, 雷达特征中的VV极化Synthetic aperture radar features VV polarization | 7978.85 |
归一化物候指数Normalized difference phenology index, NDPI | 7947.32 |
土壤调整植被指数Soil adjusted vegetation index, SAVI | 7896.25 |
表2 不同识别特征的重要性排名
Table 2 Rank of feature importance
识别特征Feature | 特征重要性Feature importance |
---|---|
海拔Elevation | 8771.81 |
VH, 雷达特征中的VH极化Synthetic aperture radar features VH polarization | 8210.86 |
归一化水指数Normalized difference water index, NDWI | 8128.18 |
简单比值Sample ratio, SR | 7979.18 |
VV, 雷达特征中的VV极化Synthetic aperture radar features VV polarization | 7978.85 |
归一化物候指数Normalized difference phenology index, NDPI | 7947.32 |
土壤调整植被指数Soil adjusted vegetation index, SAVI | 7896.25 |
图5 不同模型的耕地识别结果基于自然资源部标准地图服务网站甘S(2023)58号标准地图制作,底图边界无修改。The map was based on the standard map service website of the Ministry of Nature Resources with the drawing review No.gan S(2023)58, and the base map borders were not modified.
Fig.5 Cultivated land identification result of random forest, support vector machine and classification and regression tree respectively
模型 Model | 总精度 Overall accuracy | 用户精度 User’s accuracy | 生产者精度 Producer’s accuracy | 卡帕系数 Kappa coefficient |
---|---|---|---|---|
随机森林Random forest, RF | 0.9004 | 0.9540 | 0.9747 | 0.7944 |
支持向量机Support vector machine, SVM | 0.8868 | 0.9466 | 0.9694 | 0.7660 |
分类回归树Classification and regression trees, CART | 0.8547 | 0.9467 | 0.9494 | 0.7054 |
表3 RF、SVM、CART模型分类精度比较
Table 3 Comparison of accuracy of random forest, support vector machine, and classification and regression tree
模型 Model | 总精度 Overall accuracy | 用户精度 User’s accuracy | 生产者精度 Producer’s accuracy | 卡帕系数 Kappa coefficient |
---|---|---|---|---|
随机森林Random forest, RF | 0.9004 | 0.9540 | 0.9747 | 0.7944 |
支持向量机Support vector machine, SVM | 0.8868 | 0.9466 | 0.9694 | 0.7660 |
分类回归树Classification and regression trees, CART | 0.8547 | 0.9467 | 0.9494 | 0.7054 |
图6 本研究与Sentinel-2 10 m LULC和ESA WorldCover 10产品耕地识别结果比较基于自然资源部标准地图服务网站甘S(2023)60号标准地图制作,底图边界无修改。The map was based on the standard map service website of the Ministry of Nature Resources with the drawing review No.gan S(2023)60, and the base map borders were not modified. a、b、c分别代表图中三个展示区域a, b and c represent the three display areas in the figure respectively.
Fig.6 Comparison of this study, Sentinel-2 10 m LULC and ESA WorldCover 10
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