A framework to enhance semantic flexibility for analysis of distributed phenomena     

J. McIntosh  M. Yuan 《International journal of geographical information science》2013,27(10):999-1018

While some geographic phenomena hold uniform properties, such as land‐use zones, many geographic phenomena are distributed such that their properties vary across an extended area. While such distributed phenomena are best represented as continuous surfaces, individual objects (or features) often emerge among clusters of high or low values in a field. For example, areas of relatively high elevation may be viewed as hills, while flat low‐lying areas are perceived as plains in a terrain. A comprehensive spatial analysis of distributed phenomena should examine both the spatial variance of its attribute surfaces and the characteristics of individual objects embedded in the field. An immediate research challenge to meet such spatial analysis needs is that these emerging features often have vague boundaries that vary according to the use and the user. The nature, and even existence, of these objects depend upon the range of values, or thresholds, used to define them. We propose a representation framework that takes a dual raster‐vector approach to capture both field‐ and object‐like characteristics of distributed phenomena and maintain multiple representations of embedded features delineated by boundaries that are likely to be relevant for the expected uses of the data. We demonstrate how boundaries influence the analysis and understanding of spatiotemporal characteristics of distributed phenomena. Using precipitation as a proof of concept, we show how the proposed framework enhances semantic flexibility in spatiotemporal query and analysis of distributed phenomena in geographic information systems.  相似文献   

A context-aware personalized travel recommendation system based on geotagged social media data mining   总被引：1，自引：0，他引：1  

Abdul Majid  Gencai Chen  Hamid Turab Mirza  Ibrar Hussain  John Woodward 《International journal of geographical information science》2013,27(4):662-684

The proliferation of digital cameras and the growing practice of online photo sharing using social media sites such as Flickr have resulted in huge volumes of geotagged photos available on the Web. Based on users' traveling preferences elicited from their travel experiences exposed on social media sites by sharing geotagged photos, we propose a new method for recommending tourist locations that are relevant to users (i.e., personalization) in the given context (i.e., context awareness). We obtain user-specific travel preferences from his/her travel history in one city and use these to recommend tourist locations in another city. Our technique is illustrated on a sample of publicly available Flickr dataset containing photos taken in various cities of China. Results show that our context-aware personalized method is able to predict tourists' preferences in a new or unknown city more precisely and generate better recommendations compared to other state-of-the-art landmark recommendation methods.  相似文献   

基于Geohash的面数据区域查询   总被引：1，自引：0，他引：1  

金安  程承旗  宋树华  陈波 《地理与地理信息科学》2013,29(5)

鉴于Geohash编码的全球唯一性、多层次递归性和一维的特性,以及Geohash目前通常只用于邻近点数据的空间查询而鲜用于面数据空间查询的现状,提出了一种基于Geohash的面数据区域查询方案,描述了对面数据和查询区域的处理方法.主要思路是将面数据关联到若干Geohash单元网格,并在数据库中保存网格的Geohash编码与面数据的对应关系,查询时将查询区域根据规则对应到最多4个Geohash编码,再根据编码查询与区域相交的面数据.通过对比试验可知,在数据量较大且查询区域较小的情况下,基于Geohash编码的面数据查询效率较基于经纬度和R-树的查询效率高,在海量空间数据检索上具有一定应用价值.  相似文献   

分布式空间拓扑连接查询优化处理算法     

杨典华 《地球信息科学学报》2013,15(5):643-648,679

针对传统分布式数据库查询应用于分布式空间数据库查询带来的传输和处理代价高的问题,本文结合已有分布式跨边界片段连接优化方法,深入研究了分布式空间拓扑连接查询处理,提出跨边界连接优化的空间查询优化算法,丰富了传统的分布式查询的关系代数等价变换规则。同时,针对不同片段连接类型的分布式空间查询全局优化策略,实现了分布式空间查询分解与数据本地化,从而优化分布式查询中的数据传输所付出的高昂代价。最后,提出了结点归并、连接归并树、执行结点、执行计划树等分布式查询优化方法,利用相应归并和优化算法将全局空间查询转化为各个场地局部空间数据库的具体执行计划,消除分布式查询中的冗余计算,优化查询计算策略,从而解决分布式空间查询中的处理代价高的问题。通过分布式空间查询实验表明,本文的算法能够较好地提高分布式空间查询的性能。  相似文献   

从造船的条件要求质疑“船台说”     

金行德 《热带地理》2009,29(2)

广州"秦汉造船遗址"根本就不存在,只不过是少数人的主观臆造而已."船台说"者采取先定性后论证及排斥不同意见的做法,具有一定的欺骗性.实际上,所谓的"造船遗址"并不具备造船的基本要素,文中提出了一系列"船台说"者无法自圆其说的问题.最后呼吁"船台说"者及政府有关部门采取实事求是的负责的态度,促成问题的早日解决.  相似文献   

基于GIS的银行管理系统   总被引：5，自引：0，他引：5  

宋美遐 《测绘科学》2006,31(5):146-147,62

为了提高银行服务质量和其竞争力,可以利用GIS提供广泛的地理查询功能,辅助决策功能和客户服务功能。以营业系统的各种营业业务网点及相关资源为主要内容,建立营业网点GIS查询系统,将有以下的特点:通过GIS技术为客户提供更方便、更快捷的咨询、业务受理服务;把银行的营业网点、分理处、ATM机、自助等各种资源通过GIS技术有机地联系起来,并通过电子地图展现出来,为银行各个部门的自身业务管理以及领导的综合决策提供可靠的GIS信息基础。  相似文献   

城市多媒体地理信息查询系统的开发与研究     

向红梅  李跃 《测绘与空间地理信息》2004,27(3):23-25

多媒体地理信息系统是集地理信息、音频、视频、图像、3维动画、文本、表格和数据库等于一体的应用型地理信息系统,文中主要论述了利用先进的地理信息、多媒体和数据库技术开发城市多媒体地理信息查询系统的设计思想、技术特点和开发方法。  相似文献   

地质调查遥感数据服务系统设计与实现     

王文志  白云鹏  王磊  高振宇  杨治 《地质力学学报》2012,18(3):296-305

地质调查中的遥感影像及地理空间信息数据量大,种类繁多,基于MapGuide平台建立的地质调查遥感数据服务系统,面向野外地质调查人员与管理人员,可实现海量基础遥感影像数据、专题产品数据以及相关矢量和高程等数据的存储、发布、下载和综合管理等功能。系统在相关野外地质调查单位示范应用,取得了良好效果。   相似文献   

Spatiotemporal data model for network time geographic analysis in the era of big data   总被引：1，自引：0，他引：1  

Bi Yu Chen  Hui Yuan  Shih-Lung Shaw  William H.K. Lam  Xiaoling Chen 《International journal of geographical information science》2016,30(6):1041-1071

There has been a resurgence of interest in time geography studies due to emerging spatiotemporal big data in urban environments. However, the rapid increase in the volume, diversity, and intensity of spatiotemporal data poses a significant challenge with respect to the representation and computation of time geographic entities and relations in road networks. To address this challenge, a spatiotemporal data model is proposed in this article. The proposed spatiotemporal data model is based on a compressed linear reference (CLR) technique to transform network time geographic entities in three-dimensional (3D) (x, y, t) space to two-dimensional (2D) CLR space. Using the proposed spatiotemporal data model, network time geographic entities can be stored and managed in classical spatial databases. Efficient spatial operations and index structures can be directly utilized to implement spatiotemporal operations and queries for network time geographic entities in CLR space. To validate the proposed spatiotemporal data model, a prototype system is developed using existing 2D GIS techniques. A case study is performed using large-scale datasets of space-time paths and prisms. The case study indicates that the proposed spatiotemporal data model is effective and efficient for storing, managing, and querying large-scale datasets of network time geographic entities.  相似文献   

Indexing large geographic datasets with compact qualitative representation     

Zhiguo Long  Matt Duckham  Sanjiang Li  Steven Schockaert 《International journal of geographical information science》2016,30(6):1072-1094

This paper develops a new mechanism to efficiently compute and compactly store qualitative spatial relations between spatial objects, focusing on topological and directional relations for large datasets of region objects. The central idea is to use minimum bounding rectangles (MBRs) to approximately represent region objects with arbitrary shape and complexity and only store spatial relations that cannot be unambiguously inferred from the relations of corresponding MBRs. We demonstrate, both in theory and practice, that our approach requires considerably less construction time and storage space, and can answer queries more efficiently than the state-of-the-art methods.  相似文献