基于拓扑构建的多边形区域间运算的新方法     

陈波  薛本新  钱海忠  邓红艳 《测绘科学技术学报》2006,23(6):444-447

提出了一种新的直观的方法进行多边形区域之间的运算.首先将需要计算的多边形区域的边进行自动拓扑构建,利用多边形区域的边将平面划分为n个小多边形区域;然后生成这些多边形区域的内点,通过判断小多边形区域的内点是否在原始多边形区域内来确定小多边形区域是否选取;最后合并选取的小多边形即为所求.试验结果表明,该方法思路清晰、鲁棒性强,在GIS中得到了有效的运用.  相似文献   

基于动态树结构的河网分析方法     

艾自兴  牛瑞芳  毋河海  谌虎 《测绘科学》2006,31(3):80-81

某条河流除了河流自身的数量与质量特征外,该河流在河网结构中的空间位置及其相关结构特征将提供全局性的评价依据。河网的空间形态结构特征由各条河流的几何特征和河流之间的相互关系决定,为了完整表示河网的空间形态结构特征,本文提出了基于动态树结构的河网分析思想,阐述了动态河网树结构的建立、维护及其应用的方法。  相似文献   

On Methods of Teaching Geography     

《The Journal of geography》2012,111(2):70-76

This study investigates the location and varying spatiality of questions in geography textbooks. The results show that study questions posed in page margins address the three components of spatial thinking—concepts of space, using tools of representation, and processes of reasoning—more than questions in other locations within the text. Three practices are particularly recommended to help students develop spatial thinking skills through answering textbook questions: (1) utilize page-margin questions; (2) select questions around spatial representations; and (3) focus on higher-level cognitive processes.  相似文献   

Spatial Thinking Concepts in Early Grade-Level Geography Standards     

《The Journal of geography》2012,111(5):169-180

ABSTRACT

Research in the cognition and learning sciences has demonstrated that the human brain contains basic structures whose functions are to perform a variety of specific spatial reasoning tasks and that children are capable of learning basic spatial concepts at an early age. There has been a call from within geography to recognize research on spatial cognition in a meaningful way in primary school curriculum. This article utilizes the spatial thinking taxonomy proposed by Gersmehl and Gersmehl (2006) to examine to the extent to which spatial thinking concepts are being practiced in U.S. schools. The National Geography Standards and forty-nine state social studies or geography standards are examined. Using standards as a measure of geography content, it is concluded that while some of spatial thinking concepts appear often in curriculum, others are largely absent. Designing geography standards that address the findings of spatial cognition research may serve as a means of improving geography instruction.  相似文献   

An Evaluation of University World Geography Textbook Questions for Components of Spatial Thinking     

《The Journal of geography》2012,111(5):208-219

ABSTRACT

Geography textbooks contain chapter or review questions that may engage students in spatial thinking. This research used Jo and Bednarz’s (2009) Taxonomy of Spatial Thinking to evaluate the percentage of spatial thinking questions in four university-level world geography course textbooks. The results from this study were then compared to the findings in Jo and Bednarz’s (2009) analysis of high school geography textbooks. Thirty-five percent of university level textbook questions are related to spatial thinking compared to twenty-four percent in high school geography textbooks. The results provide information useful to stakeholders, such as teachers, administrators, and textbook writers and may help these stakeholders to consciously incorporate the three components of spatial thinking as defined by the National Research Council (2006). A simplified taxonomy for identifying spatial-thinking concepts in textbook review questions is also suggested.  相似文献   

一种基于多分辨率拓扑网络的高质量初始图斑对象生成方法     

左志权  张祖勋  张剑清 《测绘学报》2012,41(1):65-0

本文设计一种基于多分辨率拓扑网络的拓扑启发式影像分割算法,并对其涉及关键性技术进行探讨。通过细致分割实验,验证了采用该分割算法生成高质量图斑对象的可行性。  相似文献   

平面离散点集拓扑邻近稳定区域计算模型     

刘万增  陈军  闫超德  赵仁亮  赵勇  孙文彬 《测绘学报》2012,41(1):127-0

本文利用Voronoi图及其对偶Delaunay三角网研究了平面离散点集拓扑邻近稳定区域的计算方法,证明了点的拓扑邻近稳定区域必须满足的两个条件,给出了点的拓扑邻近稳定区域定量计算模型,并通过实验证明其正确性。  相似文献   

拨地工程坐标成果的自动化输出   总被引：1，自引：1，他引：0  

刘延松 《北京测绘》2012,(1):56-59

使用AutoCAD软件来计算拨地工程的坐标成果较传统计算器人工计算是一个巨大的进步,即便如此,当遇到包含多个地块的拨地工程时,逐个地块完成计算并填写成果表格,工作量仍然很大,而且对于作业过程中局部小的调整还要进行大量重复工作,并且人工干涉多,容易出现纰漏。本文介绍利用自动搜索封闭地块多边形的图形算法,实现拨地工程地块坐标成果的自动化输出,从根本上解决了传统方法效率低、人工干涉多、易出错等问题。  相似文献   

案例推理的制图综合应用背景与方法     

何海威  钱海忠  刘闯  谢丽敏 《测绘科学技术学报》2017,34(4)

从挖掘和利用经验数据的角度出发,提出了基于案例推理的智能化制图综合方法。首先探讨了基于算法和模型的自动综合实现方式所面临的瓶颈,并提出了采用制图综合案例推理辅助制图综合的思想;然后设计了制图综合专家案例的三元表示方法,以及获取、使用和管理流程;最后对实现该基于案例推理的智能化制图综合方法的五个关键性步骤进行了分析,并深入阐述该方法的原理和可行性,提出了基于案例推理的智能综合辅助系统架构。  相似文献   

Context inference and prediction modeling in ubiquitous health GIS          下载免费PDF全文

Neda Kaffash‐Charandabi  Ali‐Asghar Alesheikh 《Transactions in GIS》2017,21(6):1098-1114

The ever‐increasing population in cities intensifies environmental pollution that increases the number of asthmatic patients. Other factors that may influence the prevalence of asthma are atmospheric parameters, physiographic elements and personal characteristics. These parameters can be incorporated into a model to monitor and predict the health conditions of asthmatic patients in various contexts. Such a model is the base for any asthma early warning system. This article introduces a novel ubiquitous health system to monitor asthmatic patients. Ubiquitous systems can be effective in monitoring asthmatic patients through the use of intelligent frameworks. They can provide powerful reasoning and prediction engines for analyzing various situations. Our proposed model encapsulates several tools for preprocessing, reasoning and prediction of asthma conditions. In the preprocessing phase, outliers in the atmospheric datasets were detected and missing sensor data were estimated using a Kalman filter, while in the reasoning phase, the required information was inferred from the raw data using some rule‐based inference techniques. The asthmatic conditions of patients were predicted accurately by a Graph‐Based Support Vector Machine in a Context Space (GBSVMCS) which functions anywhere, anytime and with any status. GBSVMCS is an improved version of the common Support Vector Machine algorithm with the addition of unlabeled data and graph‐based rules in a context space. Based on the stored value for a patient's condition and his/her location/time, asthmatic patients can be monitored and appropriate alerts will be given. Our proposed model was assessed in Region 3 of Tehran, Iran for monitoring three different types of asthma: allergic, occupational and seasonal asthma. The input data to our system included air pollution data, the patients’ personal information, patients’ locations, weather data and geographical information for 270 different situations. Our results showed that 90% of the system's predictions were correct. The proposed model also improved the estimation accuracy by 15% in comparison to conventional methods.  相似文献