{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T18:09:24Z","timestamp":1779905364691,"version":"3.53.1"},"reference-count":35,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2023,3,24]],"date-time":"2023-03-24T00:00:00Z","timestamp":1679616000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41771315"],"award-info":[{"award-number":["41771315"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["42125705"],"award-info":[{"award-number":["42125705"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Key Research and Development Program of Shaanxi Province","award":["2023-YBNY-217"],"award-info":[{"award-number":["2023-YBNY-217"]}]},{"name":"Key Research and Development Program of Shaanxi Province","award":["2023-ZDLNY-69"],"award-info":[{"award-number":["2023-ZDLNY-69"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJGI"],"abstract":"<jats:p>The positive and negative terrains (P\u2013N terrains) of the Loess Plateau of China are important geographical topography elements for measuring the degree of surface erosion and distinguishing the types of landforms. Loess shoulder-lines are an important terrain feature in the Loess Plateau and are often used as a criterion for distinguishing P\u2013N terrains. The extraction of shoulder lines is important for predicting erosion and recognising a gully head. However, existing extraction algorithms for loess shoulder-lines in areas with insignificant slopes need to be improved. This study proposes a regional fusion (RF) method that integrates the slope variation-based method and region-growing algorithm to extract loess shoulder-lines based on a Digital Elevation Model (DEM) at a spatial resolution of 5 m. The RF method introduces different terrain factors into the growth standards of the region-growing algorithm to extract loess-shoulder lines. First, we employed a slope-variation-based method to build the initial set of loess shoulder-lines and used the difference between the smoothed and real DEMs to extract the initial set for the N terrain. Second, the region-growing algorithm with improved growth standards was used to generate a complete area of the candidate region of the loess shoulder-lines and the N terrain, which were fused to generate and integrate contours to eliminate the discontinuity. Finally, loess shoulder-lines were identified by detecting the edge of the integrated contour, with results exhibiting congregate points or spurs, eliminated via a hit-or-miss transform to optimise the final results. Validation of the experimental area of loess ridges and hills in Shaanxi Province showed that the accuracy of the RF method based on the Euclidean distance offset percentage within a 10-m deviation range reached 96.9% compared to the manual digitalisation method. Based on the mean absolute error and standard absolute deviation values, compared with Zhou\u2019s improved snake model and the bidirectional DEM relief-shading methods, the proposed RF method extracted the loess shoulder-lines highly accurately.<\/jats:p>","DOI":"10.3390\/ijgi12040140","type":"journal-article","created":{"date-parts":[[2023,3,27]],"date-time":"2023-03-27T01:38:36Z","timestamp":1679881116000},"page":"140","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["An Optimised Region-Growing Algorithm for Extraction of the Loess Shoulder-Line from DEMs"],"prefix":"10.3390","volume":"12","author":[{"given":"Zihan","family":"Liu","sequence":"first","affiliation":[{"name":"College of Information Engineering, Northwest A&F University, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4605-8577","authenticated-orcid":false,"given":"Hongming","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Northwest A&F University, Xianyang 712100, China"},{"name":"Agricultural Information Intelligent Sensing and Analysis Engineering Technology Research Center, Xianyang 712100, China"},{"name":"Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture and Rural Affairs, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9881-5539","authenticated-orcid":false,"given":"Liang","family":"Dong","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Northwest A&F University, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhitong","family":"Sun","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Northwest A&F University, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shufang","family":"Wu","sequence":"additional","affiliation":[{"name":"College of Water Resources and Architectural Engineering, Northwest A&F University, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Biao","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Water Resources and Architectural Engineering, Northwest A&F University, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linlin","family":"Yuan","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Northwest A&F University, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhenfei","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Northwest A&F University, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qimeng","family":"Jia","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Northwest A&F University, Xianyang 712100, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"100493","DOI":"10.1016\/j.envdev.2019.100493","article-title":"Soil erosion control practices in the Chinese Loess Plateau: A systematic review","volume":"34","author":"Wen","year":"2020","journal-title":"Environ. 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