{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T21:19:36Z","timestamp":1780694376931,"version":"3.54.1"},"reference-count":52,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,6,26]],"date-time":"2020-06-26T00:00:00Z","timestamp":1593129600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Open foundation of Jiangsu Key Laboratory of Information Agriculture","award":["KLIAKF1801"],"award-info":[{"award-number":["KLIAKF1801"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41571171"],"award-info":[{"award-number":["41571171"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012246","name":"Priority Academic Program Development of Jiangsu Higher Education Institutions","doi-asserted-by":"publisher","award":["PAPD"],"award-info":[{"award-number":["PAPD"]}],"id":[{"id":"10.13039\/501100012246","id-type":"DOI","asserted-by":"publisher"}]},{"name":"DFF-Danish ERC Support Program","award":["116491, 9127-00001B"],"award-info":[{"award-number":["116491, 9127-00001B"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Winter wheat is one of the major cereal crops in China. The spatial distribution of winter wheat planting areas is closely related to food security; however, mapping winter wheat with time-series finer spatial resolution satellite images across large areas is challenging. This paper explores the potential of combining temporally aggregated Landsat-8 OLI and Sentinel-2 MSI data available via the Google Earth Engine (GEE) platform for mapping winter wheat in Shandong Province, China. First, six phenological median composites of Landsat-8 OLI and Sentinel-2 MSI reflectance measures were generated by a temporal aggregation technique according to the winter wheat phenological calendar, which covered seedling, tillering, over-wintering, reviving, jointing-heading and maturing phases, respectively. Then, Random Forest (RF) classifier was used to classify multi-temporal composites but also mono-temporal winter wheat development phases and mono-sensor data. The results showed that winter wheat could be classified with an overall accuracy of 93.4% and F1 measure (the harmonic mean of producer\u2019s and user\u2019s accuracy) of 0.97 with temporally aggregated Landsat-8 and Sentinel-2 data were combined. As our results also revealed, it was always good to classify multi-temporal images compared to mono-temporal imagery (the overall accuracy dropped from 93.4% to as low as 76.4%). It was also good to classify Landsat-8 OLI and Sentinel-2 MSI imagery combined instead of classifying them individually. The analysis showed among the mono-temporal winter wheat development phases that the maturing phase\u2019s and reviving phase\u2019s data were more important than the data for other mono-temporal winter wheat development phases. In sum, this study confirmed the importance of using temporally aggregated Landsat-8 OLI and Sentinel-2 MSI data combined and identified key winter wheat development phases for accurate winter wheat classification. These results can be useful to benefit on freely available optical satellite data (Landsat-8 OLI and Sentinel-2 MSI) and prioritize key winter wheat development phases for accurate mapping winter wheat planting areas across China and elsewhere.<\/jats:p>","DOI":"10.3390\/rs12122065","type":"journal-article","created":{"date-parts":[[2020,6,29]],"date-time":"2020-06-29T11:17:17Z","timestamp":1593429437000},"page":"2065","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":47,"title":["Mapping Winter Wheat with Combinations of Temporally Aggregated Sentinel-2 and Landsat-8 Data in Shandong Province, China"],"prefix":"10.3390","volume":"12","author":[{"given":"Feng","family":"Xu","sequence":"first","affiliation":[{"name":"College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0287-8197","authenticated-orcid":false,"given":"Zhaofu","family":"Li","sequence":"additional","affiliation":[{"name":"College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shuyu","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Naitao","family":"Huang","sequence":"additional","affiliation":[{"name":"College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zongyao","family":"Quan","sequence":"additional","affiliation":[{"name":"College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wenmin","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Geography, Nanjing Normal University, Nanjing 210023, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7593-085X","authenticated-orcid":false,"given":"Xiaojun","family":"Liu","sequence":"additional","affiliation":[{"name":"College of Agriculture, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaosan","family":"Jiang","sequence":"additional","affiliation":[{"name":"College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianjun","family":"Pan","sequence":"additional","affiliation":[{"name":"College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2375-1651","authenticated-orcid":false,"given":"Alexander V.","family":"Prishchepov","sequence":"additional","affiliation":[{"name":"Department of Geosciences and Natural Resource Management, University of Copenhagen, 1350 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,6,26]]},"reference":[{"key":"ref_1","unstructured":"Food and Agriculture Organization of the United Nations (2019, September 12). 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