Land Cover Characterization in West Sudanian Savannas Using Seasonal Features from Annual Landsat Time Series
With the increasing temporal resolution of medium spatial resolution data, seasonal features are becoming more readily available for land cover characterization. However, in the tropical regions, images can be severely contaminated by clouds during the rainy season and fires during the dry season, w...
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| Format: | Article |
| Language: | English |
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MDPI AG
2016-04-01
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| Series: | Remote Sensing |
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| Online Access: | http://www.mdpi.com/2072-4292/8/5/365 |
| _version_ | 1819003781412552704 |
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| author | Jinxiu Liu Janne Heiskanen Ermias Aynekulu Eduardo Eiji Maeda Petri K. E. Pellikka |
| author_facet | Jinxiu Liu Janne Heiskanen Ermias Aynekulu Eduardo Eiji Maeda Petri K. E. Pellikka |
| author_sort | Jinxiu Liu |
| collection | DOAJ |
| description | With the increasing temporal resolution of medium spatial resolution data, seasonal features are becoming more readily available for land cover characterization. However, in the tropical regions, images can be severely contaminated by clouds during the rainy season and fires during the dry season, with possible effects to seasonal features. In this study, we evaluated the performance of seasonal features based on an annual Landsat time series (LTS) of 35 images for land cover characterization in West Sudanian savanna woodlands. First, the burnt areas were detected and removed. Second, the reflectance seasonality was modelled using a harmonic model, and model parameters were used as inputs for land cover classification and tree crown cover prediction using the random forest algorithm. Furthermore, to study the sensitivity of the approach to the burnt areas, we repeated the analyses without the first step. Our results showed that seasonal features improved classification accuracy significantly from 68.7% and 66.1% to 76.2%, and decreased root mean square error (RMSE) of tree crown cover predictions from 11.7% and 11.4% to 10.4%, in comparison to the dry and rainy season single date images, respectively. The burnt areas biased the seasonal parameters in near-infrared and shortwave infrared bands, and decreased the accuracy of classification and tree crown cover prediction, suggesting that burnt areas should be removed before fitting the harmonic model. We conclude that seasonal features from annual LTS improved land cover characterization performance, and the harmonic model, provided a simple method for computing annual seasonal features with burnt area removal. |
| first_indexed | 2024-12-20T23:26:27Z |
| format | Article |
| id | doaj.art-ed93d52944004e41961d6035e5649d22 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-12-20T23:26:27Z |
| publishDate | 2016-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-ed93d52944004e41961d6035e5649d222022-12-21T19:23:23ZengMDPI AGRemote Sensing2072-42922016-04-018536510.3390/rs8050365rs8050365Land Cover Characterization in West Sudanian Savannas Using Seasonal Features from Annual Landsat Time SeriesJinxiu Liu0Janne Heiskanen1Ermias Aynekulu2Eduardo Eiji Maeda3Petri K. E. Pellikka4Department of Geosciences and Geography, P.O. Box 68, University of Helsinki, FI-00014 Helsinki, FinlandDepartment of Geosciences and Geography, P.O. Box 68, University of Helsinki, FI-00014 Helsinki, FinlandWorld Agroforestry Centre (ICRAF), United Nations Avenue, P.O. Box 30677, 00100 Nairobi, KenyaDepartment of Geosciences and Geography, P.O. Box 68, University of Helsinki, FI-00014 Helsinki, FinlandDepartment of Geosciences and Geography, P.O. Box 68, University of Helsinki, FI-00014 Helsinki, FinlandWith the increasing temporal resolution of medium spatial resolution data, seasonal features are becoming more readily available for land cover characterization. However, in the tropical regions, images can be severely contaminated by clouds during the rainy season and fires during the dry season, with possible effects to seasonal features. In this study, we evaluated the performance of seasonal features based on an annual Landsat time series (LTS) of 35 images for land cover characterization in West Sudanian savanna woodlands. First, the burnt areas were detected and removed. Second, the reflectance seasonality was modelled using a harmonic model, and model parameters were used as inputs for land cover classification and tree crown cover prediction using the random forest algorithm. Furthermore, to study the sensitivity of the approach to the burnt areas, we repeated the analyses without the first step. Our results showed that seasonal features improved classification accuracy significantly from 68.7% and 66.1% to 76.2%, and decreased root mean square error (RMSE) of tree crown cover predictions from 11.7% and 11.4% to 10.4%, in comparison to the dry and rainy season single date images, respectively. The burnt areas biased the seasonal parameters in near-infrared and shortwave infrared bands, and decreased the accuracy of classification and tree crown cover prediction, suggesting that burnt areas should be removed before fitting the harmonic model. We conclude that seasonal features from annual LTS improved land cover characterization performance, and the harmonic model, provided a simple method for computing annual seasonal features with burnt area removal.http://www.mdpi.com/2072-4292/8/5/365Landsat time seriesland cover classificationtree crown coverrandom forestburnt area detectionBurkina Faso |
| spellingShingle | Jinxiu Liu Janne Heiskanen Ermias Aynekulu Eduardo Eiji Maeda Petri K. E. Pellikka Land Cover Characterization in West Sudanian Savannas Using Seasonal Features from Annual Landsat Time Series Remote Sensing Landsat time series land cover classification tree crown cover random forest burnt area detection Burkina Faso |
| title | Land Cover Characterization in West Sudanian Savannas Using Seasonal Features from Annual Landsat Time Series |
| title_full | Land Cover Characterization in West Sudanian Savannas Using Seasonal Features from Annual Landsat Time Series |
| title_fullStr | Land Cover Characterization in West Sudanian Savannas Using Seasonal Features from Annual Landsat Time Series |
| title_full_unstemmed | Land Cover Characterization in West Sudanian Savannas Using Seasonal Features from Annual Landsat Time Series |
| title_short | Land Cover Characterization in West Sudanian Savannas Using Seasonal Features from Annual Landsat Time Series |
| title_sort | land cover characterization in west sudanian savannas using seasonal features from annual landsat time series |
| topic | Landsat time series land cover classification tree crown cover random forest burnt area detection Burkina Faso |
| url | http://www.mdpi.com/2072-4292/8/5/365 |
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