Comparison of GF2 and SPOT6 Imagery on Canopy Cover Estimating in Northern Subtropics Forest in China
Canopy cover is an important vegetation attribute used for many environmental applications such as defining management objectives, thinning and ecological modeling. However, the estimation of canopy cover from high spatial resolution imagery is still a difficult task due to limited spectral informat...
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| Format: | Article |
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MDPI AG
2020-04-01
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| Series: | Forests |
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| Online Access: | https://www.mdpi.com/1999-4907/11/4/407 |
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| author | Jingjing Zhou Yuanyong Dian Xiong Wang Chonghuai Yao Yongfeng Jian Yuan Li Zeming Han |
| author_facet | Jingjing Zhou Yuanyong Dian Xiong Wang Chonghuai Yao Yongfeng Jian Yuan Li Zeming Han |
| author_sort | Jingjing Zhou |
| collection | DOAJ |
| description | Canopy cover is an important vegetation attribute used for many environmental applications such as defining management objectives, thinning and ecological modeling. However, the estimation of canopy cover from high spatial resolution imagery is still a difficult task due to limited spectral information and the heterogeneous pixel values of the same canopy. In this paper, we compared the capacity of two high spatial resolution sensors (SPOT6 and GF2) using three ensemble learning models (Adaptive Boosting (AdaBoost), Gradient Boosting (GDBoost), and random forest (RF)), to estimate canopy cover (CC) in a Chinese northern subtropics forest. Canopy cover across 97 plots was measured across 41 needle forest plots, 24 broadleaf forest plots, and 32 mixed forest plots. Results showed that (1) the textural features performed more importantly than spectral variables according to the number of variables in the top ten predictors in estimating canopy cover (CC) in both SPOT6 and GF2. Moreover, the vegetation indices in spectral variables had a lower relative importance value than the band reflectance variables. (2) GF2 imagery outperformed SPOT6 imagery in estimating CC when using the ensemble learning model in our data. On average across the models, the R<sup>2</sup> was almost 0.08 higher for GF2 over SPOT6. Likewise, the average RMSE and average MAE were 0.002 and 0.01 lower in GF2 than in SPOT6. (3) The ensemble learning model showed good results in estimating CC, yet the different models performed a little differently in the results. Additionally, the GDBoost model performed the best of all the ensemble learning models with R<sup>2</sup> = 0.92, root mean square error (RMSE) = 0.001 and mean absolute error (MAE) = 0.022. |
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| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-10T20:39:37Z |
| publishDate | 2020-04-01 |
| publisher | MDPI AG |
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| series | Forests |
| spelling | doaj.art-2df23a83112f441c861dcf24f443291c2023-11-19T20:46:50ZengMDPI AGForests1999-49072020-04-0111440710.3390/f11040407Comparison of GF2 and SPOT6 Imagery on Canopy Cover Estimating in Northern Subtropics Forest in ChinaJingjing Zhou0Yuanyong Dian1Xiong Wang2Chonghuai Yao3Yongfeng Jian4Yuan Li5Zeming Han6College of Horticulture and Forestry, Huazhong Agricultural University, Wuhan 430070, ChinaCollege of Horticulture and Forestry, Huazhong Agricultural University, Wuhan 430070, ChinaCollege of Horticulture and Forestry, Huazhong Agricultural University, Wuhan 430070, ChinaCollege of Horticulture and Forestry, Huazhong Agricultural University, Wuhan 430070, ChinaCollege of Horticulture and Forestry, Huazhong Agricultural University, Wuhan 430070, ChinaCollege of Horticulture and Forestry, Huazhong Agricultural University, Wuhan 430070, ChinaCollege of Horticulture and Forestry, Huazhong Agricultural University, Wuhan 430070, ChinaCanopy cover is an important vegetation attribute used for many environmental applications such as defining management objectives, thinning and ecological modeling. However, the estimation of canopy cover from high spatial resolution imagery is still a difficult task due to limited spectral information and the heterogeneous pixel values of the same canopy. In this paper, we compared the capacity of two high spatial resolution sensors (SPOT6 and GF2) using three ensemble learning models (Adaptive Boosting (AdaBoost), Gradient Boosting (GDBoost), and random forest (RF)), to estimate canopy cover (CC) in a Chinese northern subtropics forest. Canopy cover across 97 plots was measured across 41 needle forest plots, 24 broadleaf forest plots, and 32 mixed forest plots. Results showed that (1) the textural features performed more importantly than spectral variables according to the number of variables in the top ten predictors in estimating canopy cover (CC) in both SPOT6 and GF2. Moreover, the vegetation indices in spectral variables had a lower relative importance value than the band reflectance variables. (2) GF2 imagery outperformed SPOT6 imagery in estimating CC when using the ensemble learning model in our data. On average across the models, the R<sup>2</sup> was almost 0.08 higher for GF2 over SPOT6. Likewise, the average RMSE and average MAE were 0.002 and 0.01 lower in GF2 than in SPOT6. (3) The ensemble learning model showed good results in estimating CC, yet the different models performed a little differently in the results. Additionally, the GDBoost model performed the best of all the ensemble learning models with R<sup>2</sup> = 0.92, root mean square error (RMSE) = 0.001 and mean absolute error (MAE) = 0.022.https://www.mdpi.com/1999-4907/11/4/407GF2SPOT6high spatial resolutioncanopy coverensemble learning modelgray level co-occurrence matrix (GLCM) |
| spellingShingle | Jingjing Zhou Yuanyong Dian Xiong Wang Chonghuai Yao Yongfeng Jian Yuan Li Zeming Han Comparison of GF2 and SPOT6 Imagery on Canopy Cover Estimating in Northern Subtropics Forest in China Forests GF2 SPOT6 high spatial resolution canopy cover ensemble learning model gray level co-occurrence matrix (GLCM) |
| title | Comparison of GF2 and SPOT6 Imagery on Canopy Cover Estimating in Northern Subtropics Forest in China |
| title_full | Comparison of GF2 and SPOT6 Imagery on Canopy Cover Estimating in Northern Subtropics Forest in China |
| title_fullStr | Comparison of GF2 and SPOT6 Imagery on Canopy Cover Estimating in Northern Subtropics Forest in China |
| title_full_unstemmed | Comparison of GF2 and SPOT6 Imagery on Canopy Cover Estimating in Northern Subtropics Forest in China |
| title_short | Comparison of GF2 and SPOT6 Imagery on Canopy Cover Estimating in Northern Subtropics Forest in China |
| title_sort | comparison of gf2 and spot6 imagery on canopy cover estimating in northern subtropics forest in china |
| topic | GF2 SPOT6 high spatial resolution canopy cover ensemble learning model gray level co-occurrence matrix (GLCM) |
| url | https://www.mdpi.com/1999-4907/11/4/407 |
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