共查询到18条相似文献,搜索用时 953 毫秒
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针对当前海图抽选过程由于缺乏有效的海图抽选算法,而造成抽选效率不高甚至有可能漏选海图的问题,按照海图抽选原则并利用海图比例尺及海图覆盖区域信息,对船舶航行区域进行分级处理,提出了一种基于航行区域分级的海图自动抽选算法,阐述了该算法的基本思路和实现步骤,并通过实验验证了该算法的可行性。 相似文献
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Generalization is a comprehensive process. It is not simply a question of an algorithm, such as simplification, selection, displacement, and so on. Only after geometric shapes and topological properties have been understood fully, can a sound and automated generalization process be possible. This article proposes a new theoretical model for sounding generalization in digital nautical charts. First, with the aid of Delaunay triangulation, a tree structure is introduced for a hierarchical representation of the marine topography. Then, an analytical algorithm for the recognition and the measurement of the marine topography is developed through the use of the tree structure. Finally, all of the techniques mentioned above are integrated into a model for sounding generalization, of which results are illustrated with the aid of several examples. 相似文献
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Generalization is a comprehensive process. It is not simply a question of an algorithm, such as simplification, selection, displacement, and so on. Only after geometric shapes and topological properties have been understood fully, can a sound and automated generalization process be possible. This article proposes a new theoretical model for sounding generalization in digital nautical charts. First, with the aid of Delaunay triangulation, a tree structure is introduced for a hierarchical representation of the marine topography. Then, an analytical algorithm for the recognition and the measurement of the marine topography is developed through the use of the tree structure. Finally, all of the techniques mentioned above are integrated into a model for sounding generalization, of which results are illustrated with the aid of several examples. 相似文献
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港口航道图测量工作量的计算是测绘计划编排和任务管理的基础性工作,一直以来完全采用手工方式操作完成,具有计算工作量大、精度不高、容易出错等缺点。探讨了基于GIS技术的港口航道图测量工作量自动计算系统的主要研究内容,采用GIS技术中的成熟空间操作算法,系统实现了图幅各类多边形的全自动提取、自动裁剪、自动拼接、自动扩展,最终实现工作量的自动计算,从而取代繁琐的人工操作,最大限度实现工作量计算的自动化,改进测绘生产管理效率。 相似文献
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珊瑚礁是海洋生态系统的重要组成部分,对保护海洋生物多样性以及维持海洋生态平衡具有重大意义。我国南海珊瑚岛礁自然资源丰富,准确、高效地提取珊瑚岛礁信息对南海岛礁监测、管理、规划与保护具有现实意义。本研究基于我国海洋一号C卫星(HY 1C)遥感数据,对西沙永乐群岛珊瑚礁信息进行了研究与分析,提出基于HY 1C遥感数据的珊瑚礁地貌分类体系。采用全卷积神经网络U Net模型,依次通过下采样、上采样操作提取西沙永乐环礁地貌特征,实现原始影像的像素级语义分割。结果表明:基于HY 1C数据建立的地貌分类体系对活珊瑚覆盖及珊瑚生长发育条件具有指示作用,提出的基于U Net模型的珊瑚岛礁地貌信息自动提取方法,能够为我国南海珊瑚岛礁生态系统的全自动、大范围监测和评价提供相应理论基础,在珊瑚礁生态管理与评价中发挥关键作用。精度验证结果表明:U Net模型可以有效提取珊瑚礁地貌信息,采用的地貌信息提取方法具备时空泛化能力,泛化精度高于80%。 相似文献