适宜空间认知结果表达的地图形式   总被引：2，自引：0，他引：2  

艾廷华 《遥感学报》2008,12(2):347-354

心象地图是驻留在记忆中的关于地理世界空间特征认知结果的表达,具有如下特征:空间表达的非均一性、内容选取的主观性、空间定位的非确定性、度量特征上的非精确性.心象地图的可视化需要由特殊的图形形式来承担,经过分析提出了适宜这一表达特征的3种可视化技术,包括面向道路网认知表达的路网构架图、专题属性空间定位信息认知表达的面域拓扑图、虚拟网络空间导航认知的赛伯网络图.基于地图的定义,对这3种可视化形式度量特征进行了讨论,认为它们在有序量尺度上具有可度量特征.  相似文献   

简单面目标与带孔洞面目标间拓扑关系的层次表达方法   总被引：1，自引：1，他引：0  

Deng Min  李志林  Li Guang-qiang 《测绘学报》2008,37(3):0-402

带孔洞的面目标是现实中较为常见的一类复杂目标,它们之间的拓扑关系要比简单面目标复杂得多.本文基于空间划分和目标分解的思想,利用点集(拓扑学)理论中的邻域概念详细分析和描述带孔洞面目标的点集拓扑分量,这种描述方法实质上是简单面目标点集拓扑分量描述的一种自然延展.进而,对简单面目标间拓扑关系的描述和区分方法进行了扩展,层次地分析和区分简单面目标与带孔洞面目标间的拓扑关系.相比于Egenhofer等人提出的代数描述和间接表达方法,本文提出的方法是一种直接描述和层次表达的方法,并且与简单面目标间拓扑关系的表达方法是相统一的.  相似文献   

Territorial inertia versus adaptation to climate change. When local authorities discuss coastal management in a French Mediterranean region     

《Global Environmental Change》2023

Adaptation to climate change is a critical issue in coastal areas, at risk from sea-level rise, erosion, and sea flooding. In territories strongly urbanized and long oriented toward tourism and a residential economy, a change in coastal management and territorial development is hard to initiate. In Provence-Alpes-Côte d'Azur (France), a leading tourism region, this article explores how local authorities perceive climate change and talk about adaptation strategies. Interviews with municipal-level authorities, both elected officials and technical agents, reveal the influence of territorial inertia, with persistent statements promoting the beach- and residential-oriented economy and a wait-and-see attitude regarding climate change. Beach erosion is the only coastal risk interviewees really recognize, while sea-level rise and sea flooding are barely perceived. Yet evidence supporting the possibility of a future change in position is provided by the younger generation of interviewees, who are more aware of environmental challenges. Providing original data for a coastal region often considered as a model of development throughout the world, this article also proposes an original and transferable method combining geographical sampling of municipalities, text statistics and qualitative analysis of interviews, to apprehend the social representations of the coast, of climate change and coastal risks. Such a methodology is recommended prior to any quantitative assessment of climate action at local scale.  相似文献   

一维全非线性Green-Naghdi水波方程数值模型     

焦子峰  尹晶  房克照  孙家文 《海洋工程》2016,34(6):30-37

建立了求解一维全非线性Green-Naghdi水波方程的中心有限体积/有限差分混合数值格式。采用结构化网格对守恒形式的控制方程进行离散和积分,界面数值通量采用有限体积法计算,剩余项则采用中心有限差分格式求解。其中,采用中心迎风有限体积格式计算控制体界面数值通量,并结合界面变量的线性重构方法,使其在空间上具有四阶精度,通过引入静压重构技术和波浪破碎指标使模型具备处理海岸水-陆动边界及波浪破碎的能力。时间积分则采用具有总时间变差减小(Total Variation Diminishing,TVD)性质的三阶龙格-库塔法进行。应用该模型对孤立波在常水深和斜坡海岸上的传播过程及规则波跨越潜堤传播的实验进行了数值模型研究,数值计算同解析解及实验数据吻合良好。  相似文献   

Numerical and Experimental Studies on the Effect of Axial Spacing on Hydrodynamic Performance of the Hybrid CRP Pod Propulsion System     

熊鹰  张可  王展智  齐万江 《海洋工程》2016,(4):627-636

The hydrodynamic performance of a hybrid CRP pod propulsion system was studied by RANS method with SST turbulence model and sliding mesh. The effect of axial spacing on the hydrodynamic performance of the hybrid CRP pod propulsion system was investigated numerically and experimentally. It shows that RANS with the sliding mesh method and SST turbulence model predicts accurately the hydrodynamic performance of the hybrid CRP pod propulsion system. The axial spacing has little influence on the hydrodynamic performance of the forward propeller, but great influence on that of the pod unit. Thrust coefficient of the pod unit declines with the increase of the axial spacing, but the trend becomes weaker, and the decreasing amplitude at the lower advance coefficient is larger than that at the higher advance coefficient. The thrust coefficient and open water efficiency of the hybrid CRP pod propulsion system decrease with the increase of the axial spacing, while the torque coefficient keeps almost constant. On this basis, the design principle of axial spacing of the hybrid CRP pod propulsion system was proposed.  相似文献   

三维室内地图表达方法研究与应用     

李强  夏青  邓晨 《地理信息世界》2016,(5):28-33

室内地图是室内空间信息的载体,是实现室内位置服务的基础。本文在当前研究和应用的基础上,从室内空间整体轮廓、单楼层和多楼层叠加3个层次对室内空间轮廓、室内通道要素、室内空间单元的表达方法进行了研究与实践,并以广州白云万达广场为例,基于Web前端3D引擎threejs实现了三维室内地图的表达和应用。通过该方法,用户可以对室内空间从整体到局部进行全面了解,满足室内地图应用和导航的需求,从而提高人们对室内空间的认知效果。  相似文献   

遥感云分类不确定性的多维混合熵模型评价     

吴浩  程志萍  史文中  周璐 《测绘科学》2016,41(5):50-54,176

针对遥感影像提取信息分类过程中存在随机不确定性和模糊不确定性两种噪声,影响分类结果的准确性问题,该文在多光谱遥感影像处理中,通过对传统的混合熵模型进行多维化改进,提出多维混合熵的不确定性评价模型。采用云算法对遥感影像进行解译分类,获取相应的不确定性模型参数计算出信息熵和模糊熵,从像元和类别两个尺度构建出遥感云分类不确定性的多维混合熵评价模型。结果表明,多维混合熵模型能够充分考虑多光谱遥感数据的多维性,可以从不同尺度对遥感分类的随机不确定性和模糊不确定性进行有效全面地评价。  相似文献   

遥感卫星影像K-SVD稀疏表示去噪     

夏琴  邢帅  马东洋  莫德林  李鹏程  葛忠孝 《遥感学报》2016,20(3):441-449

常规的去噪方法在去除遥感卫星影像噪声时,往往会造成影像模糊和空间分辨率下降。本文将稀疏表示理论应用于遥感卫星影像去噪,提出了一种改进算法,能够保留低频信息不变,仅对影像的高频信息进行稀疏重建。算法核心是按照是否能够从过完备字典中选择较少原子进行稀疏表示的原则来区分高频信息中的有效信息和噪声。通过3组实验对改进算法与传统去噪方法进行对比检测,实验结果表明,改进算法在去除噪声的同时,能较好地突出影像的边缘和细节信息。  相似文献   

资源三号测绘卫星 DSM 与AST ER GDEM 精度对比分析--以高海拔山区为例     

张弛  葛莹  王冲  肖胜昌  李云婷  张骏源 《测绘工程》2016,25(8)

为了评价国产资源三号测绘卫星DSM数据质量,选取地貌类型丰富的云南省高海拔山区为试验样区,以1∶10 000实测地形图DEM为假定真值,以30m分辨率ASTER GDEM为评价参照,从高程精度和地形描述精度两方面着手,对国产资源三号测绘卫星DSM数据精确性进行分析。结果表明:国产资源三号测绘卫星DSM数据精度整体高于ASTER GDEM。  相似文献   

Numerical investigation of the scale effect of hydrodynamic performance of the hybrid CRP pod propulsion system     

《Applied Ocean Research》2016

The scale effect of hydrodynamic performance of the hybrid CRP pod propulsion system was investigated numerically using the RANS method combined with SST k − ω turbulence model and moving mesh method. The pod resistance influence factor was introduced to represent the effect of wake field of CRP on the pod resistance. Results showed the pod resistance influence factor to be a function of the Reynolds number and revolution ratio. Representative function expression can be obtained by regression analysis using multiplication of multinomial polynomials and linear function. The standard ITTC 1978 extrapolation procedure can be utilized to predict hydrodynamic performance of forward propeller because of the slightness of the influence of the pod unit on the forward propeller. The thrust and torque coefficient influence factors of aft propeller were introduced, and they were found to represent the effect of wake field of forward propeller and blockage effect of the pod on the hydrodynamic performance of aft propeller. It shows that thrust and torque coefficient influence factors are independent of the Reynolds number and have a linear relationship with the revolution ratio. On this basis, a method of estimating the hydrodynamic performance was proposed for full scale propulsion system.  相似文献