{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T18:31:51Z","timestamp":1774463511163,"version":"3.50.1"},"reference-count":57,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2021,2,26]],"date-time":"2021-02-26T00:00:00Z","timestamp":1614297600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100007782","name":"Tshwane University of Technology","doi-asserted-by":"publisher","award":["123"],"award-info":[{"award-number":["123"]}],"id":[{"id":"10.13039\/501100007782","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Improvements in irrigated areas\u2019 classification accuracy are critical to enhance agricultural water management and inform policy and decision-making on irrigation expansion and land use planning. This is particularly relevant in water-scarce regions where there are plans to increase the land under irrigation to enhance food security, yet the actual spatial extent of current irrigation areas is unknown. This study applied a non-parametric machine learning algorithm, the random forest, to process and classify irrigated areas using images acquired by the Landsat and Sentinel satellites, for Mpumalanga Province in Africa. The classification process was automated on a big-data management platform, the Google Earth Engine (GEE), and the R-programming was used for post-processing. The normalised difference vegetation index (NDVI) was subsequently used to distinguish between irrigated and rainfed areas during 2018\/19 and 2019\/20 winter growing seasons. High NDVI values on cultivated land during the dry season are an indication of irrigation. The classification of cultivated areas was for 2020, but 2019 irrigated areas were also classified to assess the impact of the Covid-19 pandemic on agriculture. The comparison in irrigated areas between 2019 and 2020 facilitated an assessment of changes in irrigated areas in smallholder farming areas. The approach enhanced the classification accuracy of irrigated areas using ground-based training samples and very high-resolution images (VHRI) and fusion with existing datasets and the use of expert and local knowledge of the study area. The overall classification accuracy was 88%.<\/jats:p>","DOI":"10.3390\/rs13050876","type":"journal-article","created":{"date-parts":[[2021,2,26]],"date-time":"2021-02-26T04:36:24Z","timestamp":1614314184000},"page":"876","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":134,"title":["Application of the Random Forest Classifier to Map Irrigated Areas Using Google Earth Engine"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5887-0904","authenticated-orcid":false,"given":"James","family":"Magidi","sequence":"first","affiliation":[{"name":"Geomatics Department, Tshwane University of Technology, Pretoria 0001, South Africa"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2944-1769","authenticated-orcid":false,"given":"Luxon","family":"Nhamo","sequence":"additional","affiliation":[{"name":"Water Research Commission of South Africa (WRC), Lynnwood Manor, Pretoria 0081, South Africa"},{"name":"Centre for Transformative Agricultural and Food Systems (CTAFS), School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg 3209, South Africa"}]},{"given":"Sylvester","family":"Mpandeli","sequence":"additional","affiliation":[{"name":"Water Research Commission of South Africa (WRC), Lynnwood Manor, Pretoria 0081, South Africa"},{"name":"School of Environmental Sciences, University of Venda, Thohoyandou 0950, South Africa"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9323-8127","authenticated-orcid":false,"given":"Tafadzwanashe","family":"Mabhaudhi","sequence":"additional","affiliation":[{"name":"School of Environmental Sciences, University of Venda, Thohoyandou 0950, South Africa"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ecolecon.2018.10.018","article-title":"Learning from the Ancient Maya: Exploring the Impact of Drought on Population Dynamics","volume":"157","author":"Kuil","year":"2019","journal-title":"Ecol. 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