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191.
采用弯曲进行道路化简冲突避免的方法 总被引:1,自引:1,他引:0
针对道路化简后可能导致要素间空间关系前后不一致的问题,提出了一种采用弯曲进行道路化简冲突避免的方法。首先,以弯曲为单元分析道路化简前后弯曲的形态变化规律,对化简过程产生的要素间空间冲突类型进行了归纳和总结;其次,基于道路弯曲与要素之间的空间关系,提出了相应的冲突判别规则;最后,利用弯曲化简的可控性和弯曲组的间接化简策略实现对化简冲突的避免。试验表明,该方法能有效地识别和避免道路化简产生的空间冲突,确保化简前后道路与其他要素空间关系的一致性。 相似文献
192.
针对专题地图制作相关研究不足的问题,该文通过归纳总结专题地图理论与应用、网络共享等方面的研究进展,从功能转变、模式转变和内涵冲击三方面分析专题地图研究趋势,并探讨现有制图理论技术存在的不足之处。文章认为:研究专题地图符号的内在结构及统一构建方式,在符号学和微观语言学的理论框架下建立专题符号句法模式,注重对专题地图符号模型的整体描述,并通过相应制图模型的研究来优化制图过程,发掘和创新制图理论成果,将会促进专题地图理论的完善,深化专题符号的自适应表达。 相似文献
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Automation of the cartographic design process is central to the delivery of bespoke maps via the web. In this paper, ontological modeling is used to explicitly represent and articulate the knowledge used in this decision-making process. A use case focuses on the visualization of road traffic accident data as a way of illustrating how ontologies provide a framework by which salient and contextual information can be integrated in a meaningful manner. Such systems are in anticipation of web-based services in which the user knows what they need, but do not have the cartographic ability to get what they want. 相似文献
196.
Obtaining spatial similarity degrees among the same objects on multi-scale maps is of importance in map generalization. This paper firstly defines the concepts of ‘map scale change’ and ‘spatial similarity degree’; then it proposes a model for calculating the spatial similarity degree between a river basin network at one scale and its generalized version at another scale. After this, it validates the new model and gets 16 points in the model validation process. The x-coordinate and y-coordinate of each point are map scale change and spatial similarity degree, respectively. Last, a formula for calculating spatial similarity degree taking map scale change as the only variable is obtained by the curve fitting method. The formula along with the model can be used to automate the algorithms for simplifying river basin networks. 相似文献
197.
Mritunjay Kumar Singh R.D. Gupta Snehmani Anshuman Bhardwaj Ashwagosha Ganju 《国际地球制图》2016,31(5):506-526
The orbital and the rational polynomial coefficients (RPC) models are the two most commonly used models to compute a three-dimensional coordinates from an image stereo-pair. But it is still confusing that with the identical user provided inputs, which one of these two models provides more accurate digital elevation model (DEM), especially for mountainous terrain. This study aimed to find out the answer by evaluating the impact of used models on the vertical accuracy of DEM extracted from Cartosat-1 stereo data. We used high-accuracy photogrammetric DEM as the reference DEM. Apart from general variations in statistics, surprisingly in a few instances, both the DEMs provided contrasting results, thus proving the significance of this study. The computed root mean square errors and linear error at 90% (LE90) were lower in case of RPC DEM for various classes of slope, aspect and land cover, thus suggesting its better relative accuracy. 相似文献
198.
North-western Anatolia has been actively deformed since Pliocene by the right-lateral North Anatolian Fault (NAF). This transform fault, which has a transtensional character in its western end due to effects from the Aegean extensional system, is a major control on the regional geomorphologic evolution. This study applied some geomorphic analyses, such as stream longitudinal profiles, stream length-gradient index, ratio of valley floor width and valley height, mountain front sinuosity, hypsometry and asymmetry factor analyses, to an area just east of the Sea of Marmara in order to understand the tectonic effects on the area’s geomorphological evolution. The active and fastest northern branch of the NAF lies within a topographic depression connecting Sea of Marmara in the east to the Adapazar? Basin in the west. This depression filled with early Pleistocene and younger sediment after a series of pull-apart basins opened along the NAF. North of this depression lies the Kocaeli Peneplain, whose southern edge the NAF uplifted. Meandering streams on the central peneplain were incised possibly due to baselevel changes in the Black Sea. South of the depression, an E-trending mountainous area has a rugged morphology. Based on geomorphic analyses, uplifted Pliocene sediment, marine terraces, and recent earthquake activity, this area between northern and southern branches of the NAF is actively uplifting. The geomorphic indices used in this study are sensitive to vertical movements rather than lateral ones. The bedrock lithology that played an important role on the area’s geomorphologic evolution also affects the geomorphic indices used here. 相似文献
199.
为了更好地与生态环境及灾害地质紧密结合,第二代全国区域地质志编制项目规定第四纪地质及地貌图为必编图件之一。图件内容包括第四纪地质体的时代、成因类型、岩性和地貌成因形态组合类型、活动断裂及海侵范围等重要地质内容,同时,附第四纪地质-地貌典型剖面和重要的地貌景点。图件特点:(1)图件的地理底图是首次用数字高程模型(DEM)数据灰度图作背景;(2)第四纪地质内容与地貌成因形态类型同编为一幅图;(3)第四纪地质体的面色用成因类型色表示;(4)地貌部分划分了不同级别成因形态类型和有特色的微地貌景点。总之,图面有立体感,地形高差明显,层次分明,色彩鲜艳,是一幅崭新的图件,可供防灾治理和地质旅游参考应用。 相似文献
200.