基于Geohash的面数据区域查询

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.     

地理空间意像模式的Voronoi模型

提出用Voronoi空间模型来表达意像模式，Voronoi模型无岐义空间邻近关系，构建能封装对象间空间关系的拓扑网络，使用该模型将各种空间介词映射为不同的拓扑结构，GIS采用该模型，可按自然语言中空间介词描述的定性空间关系查询检索模糊地理信息。     

多轨道探测资料实时查询统计系统的实现

为了实时监视新增资料的时效和质量情况，国家气象信息中心承担了“中国气象局多轨道探测资料实时监控与统计平台”项目。其中，实时资料的查询统计系统是整个项目的主要开发任务之一，该系统采用．NET技术结合水晶报表工具进行开发，提供了灵活的监视、查询和统计功能以及完善的报表操作功能。从系统分析、系统实现以及系统特点3个方面对该系统进行了详细的介绍。     

GIS空间数据索引技术研究与实现

GIS通常包含各种大量的空间信息,空间数据索引的建立有利于提高空间数据的存储、检索效率。因此,对空间数据索引模型的研究具有重要的现实意义。OracleSpatial的R-树和四叉树是索引两种空间数据索引模型和空间数据双层查询模型。在Oracle8i对象关系型的数据库管理系统中,通过空间数据和属性数据的有效结合,利用OracleSpatial提供R-树和四叉树两种空间索引方式,可实现GIS中空间数据索引、检索功能,保证了空间数据查询的快速性和准确性。     

水域地理信息系统数据查询功能开发

介绍了利用VB在GeoStar地理信息系统开发平台上进行二次开发,实现水泡子地理信息系统的数据查询功能的开发。介绍了系统的模块组成和功能以及实现各项功能的关键技术与实现方法。该系统灵活实用,功能较全,通过实际生产应用,反映出在地面水域地理信息数据计算与管理、直观显示等方面具有很大的实用价值。     

一种基于XML数据模型的时空查询代数探讨

时空查询代数是一种抽象的时空查询语言,它利用时空抽象数据类型的一部分基本的谓词、操作、函数来表达时空查询.而在时空微观运算上采用的数据结构是本源XML数据库(Native XML Database,NXD)用来存储半结构化数据的XML数据结构,所以对XML查询代数-XQuery FS的数据类型和查询操作做了时空扩展,并...     

地质调查遥感数据服务系统设计与实现

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。      

A context-aware personalized travel recommendation system based on geotagged social media data mining

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.     

A framework to enhance semantic flexibility for analysis of distributed phenomena

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.     

岩石力学参数数据库系统的开发和研究

收集大量岩石力学参数数据,利用数据预处理、统计分析、灰色系统理论、人工神经网络、经验分析等多种数据处理方法, 并参照各行业规范对力学参数取值的方法和范围,建立起岩石力学参数数据库系统。该系统可以根据工程岩体的名称、风化程度和饱水状态等工程地质情况,对实际工程中工程岩体的力学参数作出查询、预测、判断和决策。文中介绍了该系统的功能、特点、数据收录范围、数据库结构以及系统的框架组成,并以一个工程实例描述了系统的使用方法。