共查询到20条相似文献，搜索用时 922 毫秒
1.
网格DEM建模时应考虑地形断裂线等特殊地形。基于杨赤中插值法,提出了判断及处理地形断裂线之上和两侧的网格点、离散点位置关系的算法以及断裂地形三维显示的方法,通过实例验证了该方案的正确性和可行性。 相似文献
2.
利用上海市2006—2009年的盗窃案件数据,基于ArcGIS及Excel软件,运用描述性统计、核密度估计等方法,分析了上海市盗窃案件的空间分布、时间分布,以及时空分布规律。研究表明:空间上,上海市盗窃案件密度在中心城区最高,向周边区域衰减,并在远郊某些地区出现孤立热点;时间上,以时、日、月为尺度的盗窃案件分布表现出各自的周期规律;2006—2009年,盗窃案件数持续上升的区域主要是在郊区,持续下降的区域主要是在市区。研究成果能为犯罪预防以及案件侦破提供依据。 相似文献
3.
基于图形的可视化地学建模环境 总被引：5，自引：1，他引：5
概念地图是一种用于支持知识构建及知识共享的方法。通过概念地图，可以有效地创建知识，将不同用户及专家的知识以概念实体与概念关系的形式组织，以图形化的形式加以表示，来支持地学模型建模。基于概念地图的地学模型建模过程包括系统模型描述、用户模型定义、模型建造、模型解释与转换以及CASE生成几部分。随后，详细讨论了模型支持系统的应用特点，基于概念地图的空间模型建模的环境和工作流程。最后，利用永定河的水利工程等背景资料，建立了小清河分洪区背景信息的概念地图模型，利用建立的概念地图模型，在可视化建模环境下，建立了永定河洪水模拟模型。对洪水模拟结果和流域的社会经济统计数据进行叠加分析，得到了令人满意的的洪水灾情评估结果。 相似文献
4.
在虚拟地理环境（virtual geographic environments,VGE）的研究中,城市公共安全作为一种典型的应用,致力于实现风险的认知与表达。然而,针对城市突发公共事件风险评估的共享管理需求与即时性需求,尚缺乏一种面向过程的风险监测与评估的表达方法,难以提供快速、全面的决策支持。针对此问题,本文首先基于元对象设施（meta object facility,MOF）建模架构,提出统一时空框架下面向过程的风险评估建模方法,实现风险监测评估方法的共享与重用,并提供面向过程的即时风险评估个性化信息服务。其次,设计了风险评估过程管理原型系统,实现风险评估过程建模、注册、执行和可视化等功能。最后,通过试验模拟太原市燃气泄漏事件作为应用案例,验证了方法的可行性。 相似文献
5.
为了改善全景地图的可视效果,通过分析远近视野局部地形变形特征,提出了基于液化变形的地形水平局部变形方法,改善近视野的地形局部遮挡现象;利用视线追踪的地形局部降低方法和高斯变换的地形局部抬高方法,改善远视野的地形局部遮挡及地物缩小现象,避免了视野中地形的扭曲重叠,减小了由于透视投影所造成的地物遮挡及缩小现象,增强了全景景观地图的艺术视觉效果,并提高了生成全景图的算法效率。 相似文献
6.
一种地形三维数据快速采集系统的研究 总被引：2，自引：0，他引：2
研制出基于彩色地图的地形三维数据快速采集系统。它通过对彩色地图图像进行分色、定向、跟踪等处理 ,自动、快速获取高精度的地形三维数据 ,以便建立地图数据库、地形三维模型和对地理信息系统进行相应数据的更新。 相似文献
7.
三维景观旅游地图是当今旅游地图发展的一个新趋势。此类地图的编制方法是在运用传统地图语言表现地图基本地理内容的基础上,利用大比例尺的地形数据、遥感影像,通过矢量建模、标量合成叠加等技术,着力表现真实立体的地貌、建筑物和景观实景,让使用者有一目了然、身临其境的感受。三维景观旅游地图的成品既有实用性又有美观性。 相似文献
8.
9.
本文介绍了利用原始遥感影像数据、DEM数据、空三加密数据和地形矢量数据通过定向、纠正、镶嵌、编辑、复合和整饰等工序编制数字影像地图的方法，并讨论了数字影像地图的质量评估标准以及在编制过程中的质量控制方法，最后简要叙述了数字影像地图的应用现状并对其前景作了展望。 相似文献
10.
介绍利用最新卫星影像数据辅助三维建模、快速更新地图和三维地形构建三个方面的应用,通过三维数字城市建设的实践,说明卫星影像在三维电子地图建设中发挥的重要作用,并阐述了卫星影像图是网络地图中的重要表现形式之一。 相似文献
11.
12.
Population spatialization is the foundation for the visualization and analysis of population integrated with other information, such as environmental resources, economy, and public health. The existing population spatialization models have solved many problems for population distribution, but most of these studies have focused on a specific, single-scale approach and ignored the scale transformation for population spatialization. However, multi-scale visualization and the analysis of spatial information need multi-scale information. Meanwhile, the population distribution map as one kind of thematic map is always overlaid with the digital vector map or remote sensing map and visualized in the Web Geographic Information Systems (Web GIS), so it should adapt to the map scale showed in browser, when the user zoom in and zoom out. Hence adaptive multi-scale is necessary for population spatialization. Therefore, in this study, an adaptive multi-scale population spatialization model (APSM) is proposed with comprehensive factors constrained. These factors are residential area, land cover, public transport, hydrology, terrain, and climate. All of them are closely associated with population distribution. The overall methodology of APSM and the process for APSM are expounded in this paper. Meanwhile, with a case study of Russia, the processes of APSM for Russia are stated, and a population spatialization tool is implemented for expanding the application of APSM. The experimental analysis showed that APSM satisfied the requirement of geospatial analysis well and obtained a reliable accuracy. 相似文献
13.
Diversity within a population has been linked to levels of both social cohesion and crime. Neighborhood crimes are the result of a complex set of factors, one of which is weak community cohesion. This article seeks to explore the impacts of diversity on burglary crime in a range of neighborhoods, using Leeds, UK as a case study. We propose a new approach to quantifying the correlates of burglary in urban areas through the use of diversity metrics. This approach is useful in unveiling the relationship between burglary and diversity in urban communities. Specifically, we employ stepwise multiple regression models to quantify the relationships between a number of neighborhood diversity variables and burglary crime rates. The results of the analyses show that the variables that represent diversity were more significant when regressed against burglary crime rates than standard socio‐demographic data traditionally used in crime studies, which do not generally use diversity variables. The findings of this study highlight the importance of neighborhood cohesion in the crime system, and the key place for diversity statistics in quantifying the relationships between neighborhood diversities and burglary. The study highlights the importance of policy planning aimed at encouraging community building in promoting neighborhood safety. 相似文献
14.
自美国"9·11"事件发生以来,全球恐怖主义活动日益频繁,已成为21世纪城市所面临的重大安全问题。目前,对城市恐怖主义的研究也变得越来越紧要。本文以模糊层次分析法为基础,构建城市遭受恐怖袭击的风险评估模型,分析城市遭恐怖袭击的可能程度,得到我国15个大城市遭受恐怖袭击的风险排序,并用专题图展示。 相似文献
15.
Population at risk of crime varies due to the characteristics of a population as well as the crime generator and attractor places where crime is located. This establishes different crime opportunities for different crimes. However, there are very few efforts of modeling structures that derive spatiotemporal population models to allow accurate assessment of population exposure to crime. This study develops population models to depict the spatial distribution of people who have a heightened crime risk for burglaries and robberies. The data used in the study include: Census data as source data for the existing population, Twitter geo-located data, and locations of schools as ancillary data to redistribute the source data more accurately in the space, and finally gridded population and crime data to evaluate the derived population models. To create the models, a density-weighted areal interpolation technique was used that disaggregates the source data in smaller spatial units considering the spatial distribution of the ancillary data. The models were evaluated with validation data that assess the interpolation error and spatial statistics that examine their relationship with the crime types. Our approach derived population models of a finer resolution that can assist in more precise spatial crime analyses and also provide accurate information about crime rates to the public. 相似文献
16.
Serkan Ural Ejaz Hussain Jie Shan 《International Journal of Applied Earth Observation and Geoinformation》2011
Geospatial distribution of population at a scale of individual buildings is needed for analysis of people's interaction with their local socio-economic and physical environments. High resolution aerial images are capable of capturing urban complexities and considered as a potential source for mapping urban features at this fine scale. This paper studies population mapping for individual buildings by using aerial imagery and other geographic data. Building footprints and heights are first determined from aerial images, digital terrain and surface models. City zoning maps allow the classification of the buildings as residential and non-residential. The use of additional ancillary geographic data further filters residential utility buildings out of the residential area and identifies houses and apartments. In the final step, census block population, which is publicly available from the U.S. Census, is disaggregated and mapped to individual residential buildings. This paper proposes a modified building population mapping model that takes into account the effects of different types of residential buildings. Detailed steps are described that lead to the identification of residential buildings from imagery and other GIS data layers. Estimated building populations are evaluated per census block with reference to the known census records. This paper presents and evaluates the results of building population mapping in areas of West Lafayette, Lafayette, and Wea Township, all in the state of Indiana, USA. 相似文献
17.
随着PGIS平台在全国公安机关的广泛推广和深入应用,迫切需要将已有MIS业务系统与PGIS实现整合,而其中最为重要的就是如何实现基于PGIS的警务业务信息空间化问题。本文即以南京市公安局相关信息系统为例,对PGIS支持下的警务信息空间位置采集方式进行了探讨。对警务业务系统中相关信息的空间位置采集方式进行了流程设计、数据库模型研究以及业务功能实现。结果表明,这种采集方式不仅保证原有警务业务系统的稳定性以及警务业务信息空间位置采集的实时性,而且通过充分利用PGIS已有服务和功能,为PGIS与警务业务系统的充分融合提供了一定的示范作用。 相似文献
18.
Crime on the edges: patterns of crime and land use change 总被引：1，自引：0，他引：1
ABSTRACTCriminologists have long-known that different locations have varying levels of risk for criminal victimization. Based on the geometry of crime and its corresponding crime generators and crime attractors, edges (boundaries between relatively homogeneous neighborhoods) are locations with an elevated risk of criminal victimization. In this article, we investigate the importance of edges. We find that criminal victimization rates are 2–3 times on an edge compared to elsewhere. However, this effect decreases very quickly moving away from these locations, with the effect gone at 40 meters. This general effect is identified in a number of contexts and locations. 相似文献
19.
群体用户对公共地图服务的访问行为具有社会性,存在着一定的群体访问行为模式。该模式具有高强度的访问聚集性与突发性,且决定着公共地图服务对云计算资源的需求。如何有效地表达和捕捉群体用户访问聚集性及其访问强度的时序变化特征,进行准确的公共地图服务负载预测,是实现按需选择和调度云计算资源,应对海量用户并发服务挑战的关键。本文基于海量的公共地图服务用户访问日志和时间序列聚类方法,建立了群体用户访问到达行为的时序分布模型;考虑降低负载预测复杂度的同时,利用访问强度具有多峰值、变强度以及周期性的特点,分割访问到达率在一个周期内时间序列上的模式区间,实现访问强度时序聚类划分的最优;基于各访问模式区间不同的访问到达概率密度的分布,提出了基于累积概率分布的时间序列平滑预测服务负载方法,该预测方法的算法复杂度低,且所需的先验数据量小。实验证明,本文提出的基于时序的群体用户访问到达率最优分割方法及其预测方法可以以较高的准确率预测服务负载。该方法在应对海量用户并发访问挑战的同时,可提高云计算资源的利用效率,解决公共地图服务质量与服务成本的平衡性问题。 相似文献
20.
ABSTRACT In this study, we model the risk of robbery in the City of Tshwane in South Africa. We use the collective knowledge of two prominent spatial theories of crime (social disorganization theory, and crime pattern theory) to guide the selection of data and employ rudimentary geospatial techniques to create a crude model that identifies the risk of future robbery incidents in the city. The model is validated using actual robbery incidences recorded for the city. Overall the model performs reasonably well with approximately 70% of future robbery incidences accurately identified within a small subset of the overall model. Developing countries such as South Africa are in dire need of crime risk intensity models that are simple, and not data intensive to allocate scarce crime prevention resources in a more optimal fashion. It is anticipated that this model is a first step in this regard. 相似文献