Land-use and land-cover classification using Sentinel-2 data and machine-learning algorithms: operational method and its implementation for a mountainous area of Nepal

2019 ◽  
Vol 13 (01) ◽  
pp. 1 ◽  
Author(s):  
Marie Delalay ◽  
Varun Tiwari ◽  
Alan D. Ziegler ◽  
Vik Gopal ◽  
Paul Passy
2021 ◽  
Vol 13 (24) ◽  
pp. 13758
Author(s):  
Kotapati Narayana Loukika ◽  
Venkata Reddy Keesara ◽  
Venkataramana Sridhar

The growing human population accelerates alterations in land use and land cover (LULC) over time, putting tremendous strain on natural resources. Monitoring and assessing LULC change over large areas is critical in a variety of fields, including natural resource management and climate change research. LULC change has emerged as a critical concern for policymakers and environmentalists. As the need for the reliable estimation of LULC maps from remote sensing data grows, it is critical to comprehend how different machine learning classifiers perform. The primary goal of the present study was to classify LULC on the Google Earth Engine platform using three different machine learning algorithms—namely, support vector machine (SVM), random forest (RF), and classification and regression trees (CART)—and to compare their performance using accuracy assessments. The LULC of the study area was classified via supervised classification. For improved classification accuracy, NDVI (normalized difference vegetation index) and NDWI (normalized difference water index) indices were also derived and included. For the years 2016, 2018, and 2020, multitemporal Sentinel-2 and Landsat-8 data with spatial resolutions of 10 m and 30 m were used for the LULC classification. ‘Water bodies’, ‘forest’, ‘barren land’, ‘vegetation’, and ‘built-up’ were the major land use classes. The average overall accuracy of SVM, RF, and CART classifiers for Landsat-8 images was 90.88%, 94.85%, and 82.88%, respectively, and 93.8%, 95.8%, and 86.4% for Sentinel-2 images. These results indicate that RF classifiers outperform both SVM and CART classifiers in terms of accuracy.


2020 ◽  
Vol 12 (7) ◽  
pp. 1135 ◽  
Author(s):  
Swapan Talukdar ◽  
Pankaj Singha ◽  
Susanta Mahato ◽  
Shahfahad ◽  
Swades Pal ◽  
...  

Rapid and uncontrolled population growth along with economic and industrial development, especially in developing countries during the late twentieth and early twenty-first centuries, have increased the rate of land-use/land-cover (LULC) change many times. Since quantitative assessment of changes in LULC is one of the most efficient means to understand and manage the land transformation, there is a need to examine the accuracy of different algorithms for LULC mapping in order to identify the best classifier for further applications of earth observations. In this article, six machine-learning algorithms, namely random forest (RF), support vector machine (SVM), artificial neural network (ANN), fuzzy adaptive resonance theory-supervised predictive mapping (Fuzzy ARTMAP), spectral angle mapper (SAM) and Mahalanobis distance (MD) were examined. Accuracy assessment was performed by using Kappa coefficient, receiver operational curve (RoC), index-based validation and root mean square error (RMSE). Results of Kappa coefficient show that all the classifiers have a similar accuracy level with minor variation, but the RF algorithm has the highest accuracy of 0.89 and the MD algorithm (parametric classifier) has the least accuracy of 0.82. In addition, the index-based LULC and visual cross-validation show that the RF algorithm (correlations between RF and normalised differentiation water index, normalised differentiation vegetation index and normalised differentiation built-up index are 0.96, 0.99 and 1, respectively, at 0.05 level of significance) has the highest accuracy level in comparison to the other classifiers adopted. Findings from the literature also proved that ANN and RF algorithms are the best LULC classifiers, although a non-parametric classifier like SAM (Kappa coefficient 0.84; area under curve (AUC) 0.85) has a better and consistent accuracy level than the other machine-learning algorithms. Finally, this review concludes that the RF algorithm is the best machine-learning LULC classifier, among the six examined algorithms although it is necessary to further test the RF algorithm in different morphoclimatic conditions in the future.


Author(s):  
Gordana Jakovljević

Land cover/land use (LULC) have an important impact on land degradation,erosion and water availability therefore mapping of patterns and spatial distribution ofLULC is essential for land management. Accurate mapping of complex land cover andland use classes using remotely sensed data requires robust classification methods.Various classification algorithms and satellite images have been used in recent years. Forthis study, moderate resolution Sentinel-2 image was used. In order to evaluate thepotential of the input image and derive land cover map in complex urban area of BanjaLuka, Republic of Srpska with highest possible precision, two machine learningalgorithms where applied: Supported Vector Machines (SVM) and Random Forst (RF).An overall classification accuracy of 90,82% with kappa value of 0,87 and 88,29 withkappa value of 0,84 was achieved using SVM and RF. The study showed that ofmachine learning algorithms on Sentinel-2 imagery can results in accurate land covermaps.


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