| 摘要: |
| 海岸带是受人类活动和全球海平面上升影响的敏感地带, 海岸线的提取和监测是海岸带生态系统研究和社会管理的重要内容。本文在遥感和地理信息系统的支持下, 以修正的归一化水体指数(Modified Normalized Difference Water Index, MNDWI)为基础, 结合遥感影像处理和直方图均衡化等技术, 实现了大连市獐子岛1985—2016年海岸线的自动化提取。结果表明: (1)通过与三位专家目视解译的成果比对, 本文提取海岸线的精度能满足后续研究的要求(相对误差分别为0.045%, 0.032%和0.023%); (2)近30年来, 獐子岛海岸线总体呈现蚀退趋势, 岸线长度与岛屿面积分别呈现变短和变小的趋势, 獐子岛(主岛)和大耗岛的岸线蚀退速率最大, 褡裢岛次之, 小耗岛最小; 在人类活动较为密集的区域, 海岸线呈现出较为强烈的增长趋势, 海水养殖和圈海建坝是岸线增长的主要驱动力; (3)獐子岛海岸线具有显著的分形性质, 分形维数随时间呈现增大的趋势, 獐子岛(主岛)的分形维数最大, 褡裢岛的分形维数最小。 |
| 关键词: 海岸线变化 自动化提取 DSAS/LRR 分形维 獐子岛 |
| DOI：10.11759/hykx20170610001 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划(2015CB453303); 中央级公益性科研院所基本科研业务费(20603022016003) |
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| Automatic extraction of shorelines and the spatio-temporal changes: A case study of the Zhangzi Islands in Dalian city, China |
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DING Xiao-song,SHAN Xiu-juan,CHEN Yun-long,JIN Xian-shi,YANG Tao
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| Abstract: |
| The coastal zone is a sensitive area affected by human activities and global sea level rising. Shoreline extraction and monitoring is an important research area in the study of coastal zone ecosystem and social management. In this study, to obtain the shoreline of the Zhangzi Islands, Dalian city, by automatic extraction the Modified Normalized Difference Water Index (MNDWI) was used, based on remote sensing (RS) image processing, geographical information system (GIS), and histogram equalization methods. The results revealed the following: (1) By comparing the visual interpretations of three experts, the accuracy of the shoreline extraction can meet the requirements of follow-up studies (the relative errors were 0.045 %, 0.032 %, and 0.023 %). (2) In the past 30 years, the shoreline of the Zhangzi Islands showed an erosion trend, and the length of the shoreline and the area of the island decreased. The shoreline erosion rates of the Zhangzi Island (main island) and Dahao Island were the largest, followed by the Dalian Island. The Xiaohao Island had the least erosion rate. The shoreline in the area with the most intensive human activity showed a strong growth trend. (3) The Zhangzi Islands shoreline had significant fractal properties, and the fractal dimension increased with time. The fractal dimension of the Zhangzi Island (main island) was the largest, and that of the Xiaohao Island was the smallest. |
| Key words: Shoreline change Automatic extraction DSAS/LRR Fractal dimension Zhangzi Islands |
