共查询到17条相似文献,搜索用时 625 毫秒
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海图符号的基本概念、发展过程及趋势 总被引:1,自引:0,他引:1
本文阐述了海图符号的基本概念及其主要功能,介绍了从中世纪世界波托兰海图和中国明朝郑和航海图以来海图符号的发展,论述了符号学、地图符号学对海图符号学的影响。最后,从深加工和积极引进符号学和地图符号学的先进研究成果等方面提出了海图符号学今后的发展方同。 相似文献
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论述了全数字摄影测量系统(DPS)与MicroStation联机测图的方法,以及与此相关的层控对应表的制作.以实际生产作业为例,有效地提高了工作效率,降低内耗,减少了作业中间数据的相互转换,避免了有效数据的丢失,很好地保证了产品的质量. 相似文献
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依比例、不依比例和半依比例符号数学定义的修改 总被引:1,自引:0,他引:1
定义了一般地图符号后,在此基础上引入地物的真实像,通过地图符号与真实像相同、包含和半包含关系的讨论,分别推导了依比例符号、不依比例符号和半依比例符号数学定义。修改后的定义更能反映三种符号的本质特征和内在联系,定义的表达也更为简捷。 相似文献
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In current practice in the development of hydrographic information systems, the automatic acquisition of spatial data has been considered to be very difficult. One of the key problems is recognition and correct separation of a feature from a complex graphic background. For these problems, this article presents a new concept of graph subsets to describe graph structures and composition rules of symbols in nautical charts. Based on this concept, morphological methods and operations in graph theory are unified into a coherent mathematical framework specially designed for analysis and recognition of binary chart images. In particular, an experimental system composed of feature extraction, symbol recognition, geometric reasoning, and intelligent control is developed for automatic digitization of nautical charts. 相似文献