基于MPI的新型GRASS并行处理技术与体系结构研究

在总结国内外学者对并行GIS研究成果的基础上,通过对GRASS数据特征与典型算法的分析,分别给出栅格和矢量数据的数据并行策略,从数据并行角度,提出了相关处理算法整体并行的思路与新型GRASS并行系统架构.通过部分栅格与矢量GIS算法的并行化实验,初步验证其正确性和有效性,分析其适用性及优缺点,并提出下一步改进设想.该方法一方面提出了一种基于MPI的GRASS软件系统并行化的新思路,另一方面作为利用原有GIS软件系统快速搭建并行GIS实验平台的途径之一,具有工作量小,成本低的优点.     

模块化地理信息系统环境（MGE）评述

模块化地理信息系统环境（ＭＧＥ）是一个兼有矢量和栅格数据结构以及矢量、栅格分析运算功能，具有面向对象的动态分析操作的地理信息系统，同时也是一个遥感图像运算处理、地图制图系统。它几乎可在所有硬件平台上、各种操作系统下运行。除了常规的分析功能外，ＭＧＥ有如下发展趋势：ＣＬＩＰＰＥＲ工作站移向多奔腾ＣＰＵ的ＩＮＴＥＬ兼容机、面向公司和办公室的ＧＩＳＯＦＦＩＣＥ系列、具有面向对象的动态分析功能、规范化公共设施管理环境系统（ＦＲＡＭＭＥ）以及多媒体数据的管理集成系统模块ＶＩＳＴＡＭＡＰ。     

基于地理信息系统的情报应用系统的设计与实现

情报数据具有数据来源广泛、数据格式种类多、数据量大等特点.将地理信息系统技术应用于构建情报应用系统可以解决情报数据的一体化存储与管理以及矢量、栅格、多媒体等情报数据的显示、处理、分析等诸多问题.重点介绍了基于GIS的情报应用系统的体系结构、情报数据模型和系统功能,并在此基础上总结出系统的特点.     

矢量、栅格相互转换的新方法

矢量、栅格相互转换是地理信息来统(GIS)及遥感、Gis集成系统不可缺少的功能。为提高两者相互转换的效率，在分析传统转换方法的基础土，提出了经过改进的新方法-矢量、栅格转换的颜色填充法和栅格向矢量转换的散列线段聚合法。     

计算机中的位图和矢量图

位图(又称点阵图或栅格图像)和矢量图是计算机图形中的两大概念,这两种图形都被广泛应用到出版,印刷,互联网等各个方面,他们各有自己的特点,认识他们的特色和差异,有助于创建、输入、输出、编辑和应用数字图像。位图图像和矢量图形没有好坏之分,只是用途不同而已。因此,整合位图图像和矢量图形的优点,才是处理数字图像的最佳方式。     

微机遥感图像处理系统MRSIPS

MRSIPS是面向遥感应用的遥感图像处理系统与地理信息系统的综合系统,该系统具有二个重要功能:(1)用遥感数据更新 GIS 中的数据,(2)将GIS中的信息和遥感信息进行综合分析,提高分类精度     

审图系统中的图纸一致性检测算法

在审图系统中，对报送的工程图纸扫描件和先前的电子图纸的一致性检测是一个重要环节。该文将由绘图软件(如AutoCAD等)绘制的以矢量形式保存的电子图纸转化为以栅格形式存储的图像文件，再利用该栅格图像文件对扫描件进行预处理，并用小波变换和计算分形维数对扫描图纸和栅格文件进行比对。实验结果表明，该算法能够很好地实现扫描图纸和栅格文件的比对。     

GIS中实用化矢量栅格一体化技术实现

矢量栅格一体化技术是ＧＩＳ发展的一个方向，作者在实践基础上介绍了一种实用化矢量栅格一体化系统的设计、数据组织、数据匹配以及一体化分析，并列举了若干应用实例。     

栅格数据地理信息系统(Raster GIS)关键技术分析

数据是地理信息系统的基础,强大的地理信息分析功能对地图数据有很高的要求.国内外大多数应用型地理信息系统都是基于矢量地图数据格式的.这样的系统在提供便利操作的同时,增加了系统开发成本和开发周期.如果建立基于栅格数据的地理信息系统,不需要数字化编辑处理地图数据,节省了矢量化数据的成本,并且地图显示更为形象、直观.在分析栅格数据和矢量数据的基础上,探讨了基于栅格数据的地理信息系统体系框架,并就基于栅格数据的地理信息系统开发中的基本地图操作、属性查询、地图分析等关键技术进行研究,提出了一些思路和解决办法.同时,将该技术成功应用到军事演习系统中,取得了良好的效果.     

空间信息处理技术与农田地理信息系统的研究

为了满足实施精细农业定位作物管理中数据管理与分析的需要,在对空间信息处理技术研究的基础上设计开发了一个农田地理信息系统。系统除了具有农田信息管理与数据处理的功能以外,还提供了处理GPS数据与RS图像的功能,方便了3S(GIS、GPS、RS)技术的集成应用。文章介绍了系统中GPS数据的制图与平滑处理、地图坐标转换、RS图像的几何校正与坐标配准、空间插值分析以及农田信息统计和查询等主要的功能及其实现方法。在北京精准农业示范区的应用表明系统可以作为一种用于精细农业研究的数据分析与信息管理的工具。     

透射率全局估计航空影像去雾算法

针对雾霾天气会导致航空影像的色彩失真、信息损失，对影像的后期处理和判读造成了负面影响，以暗原色先验为理论基础，结合航空影像的成像特点和景物内容特点提出一种针对航空影像的去雾算法。首先，获取航空影像透射率图并对其自动分割；其次，对影像透射率全局估计和局部优化；最后，根据大气物理模型对影像恢复处理。选取了山区、村镇、城市等各种场景近20组航空影像进行试验，从主观和客观两方面对算法效果进行评价，结果表明该算法具有处理效果稳定、鲁棒性强的特点。     

Using the R statistical data analysis language on GRASS 5.0 GIS database files

Many researchers wish to explore and analyse spatial data, but typical software does not readily permit such integration. This paper presents a simple interface between two open-source software systems, the GRASS geographical information system, and the R statistical data analysis language. The platform used here is GNU/Linux, because both systems compile and install cleanly; R runs cleanly in Windows environments as well. The interface allows floating point and category data to be passed both ways for raster map layers and sites files; NULL raster cells in GRASS interchange with NA (not available) values in R. Because both systems are developing rapidly and GRASS database internals change often, the interface uses ASCII transfer via temporary files generated by standard programs. The interface operates by running R from within the GRASS environment, and issues commands to GRASS programs through the R system( ) function. The accompanying code is constructed as an R package, and contains wrapper functions for R plotting, and for R analytical functions returning gridded output, such as trend surface and kriging prediction, kernel density estimation of point patterns, and bicubic spline interpolation. These typical spatial analytical techniques, also often available in some form in GIS, are amply buttressed in R by a large range of other statistical and graphical functions, giving substantial insight into the data or results being handled. The interface will be extended to vector data, and will be coordinated with other database integration packages in R and GRASS.     

Morphometric analysis in geographic information systems: applications of free software GRASS and R

Development and interpretation of morphometric maps are important tools in studies related to neotectonics and geomorphology; Geographic Information Systems (GIS) allows speed and precision to this process, but applied methodology will vary according to available tools and degree of knowledge of each researcher about involved software.A methodology to integrate GIS and statistics in morphometric analysis is presented for the most usual morphometric parameters—hypsometry, slope, aspect, swath profiles, lineaments and drainage density, surface roughness, isobase and hydraulic gradient.The GIS used was the Geographic Resources Analysis Support System (GRASS-GIS), an open-source project that offers an integrated environment for raster and vector analysis, image processing and maps/graphics creation. Statistical analysis of parameters can be carried out on R, a system for statistical computation and graphics, through an interface with GRASS that allows raster maps and points files to be treated as variables for analysis.The basic element for deriving morphometric maps is the digital elevation model (DEM). It can be interpolated from scattered points or contours, either in raster or vector format; it is also possible to use DEMs from NASA's Shuttle Radar Topographic Mission, with 30 m of ground resolution for the USA and 90 m for other countries.Proposed methodology can be adapted according to necessities and available tools. The use of free and open-source tools guarantees access to everyone, and its increasing popularization opens new development perspectives in this research field.     

A new GRASS GIS fuzzy inference system for massive data analysis

GIS systems are frequently coupled with fuzzy logic systems implemented in statistical packages. For large GIS data sets including millions or tens of millions of cells, such an approach is relatively time-consuming. For very large data sets there is also an input/output bottleneck between the GIS and external software. The aim of this paper is to present low-level implementation of Mamdani’s fuzzy inference system designed to work with massive GIS data sets, using the GRASS GIS raster data processing engine.     

Integration of remotely-sensed raster data with a vector-based geographical information system for land-use change detection

Methods of land-use change detection are different for raster and vector data types because of the differences in structures of the two data types. Since large amounts of land-use data (derived from existing maps and aerial photographs) are stored in vector format in a Geographical Information System (GIS), there is a need to develop a change detection algorithm for use with vector-formatted data. Since remotely-sensed images are increasingly being used to derive land-use data, it is necessary to integrate raster data with large volumes of vector data already available in a GIS. This necessitates an efficient and effective data integration technique using which raster data are to be integrated with a vector-based GIS. This paper presents a methodology of data integration of remotely-sensed raster data with vector data. A new approach is developed for land-use change detection for use with vector data in a GIS environment. The approach is based on the mathematical concepts of Sets and Groups, and is successfully implemented for the analysis of historical land-use change from 1931 to 1989 in the River Glen catchment, U.K. Algorithms have been developed for automatic derivation of dynamic statistics of land-use. It is shown that this approach can be efficiently adopted for operational use incorporating products derived from both coarse- and fine-resolution remotely-sensed satellite images once these are integrated with the vector-based GIS.     

基于GIS平台的R树索引模型研究与实现

本文阐述了一种GIS平台-GRASS平台的基本结构和特点,分析了GRASS矢量图的文件结构及空间索引的几种基本算法,阐明了建立R树索引机制的一些基本思路和方法,提出了在GRASS平台上建立R树索引模型的实现策略。     

Development of a Process-Based Model for Dynamic Interaction in Spatio-Temporal GIS

Spatial processes and their interactions are fundamental in explaining the complex behavior of real world systems. Current GIS describes space based on map layers and by means of either the vector or raster model. However, current vector and raster models cannot dynamically maintain topological relationships between spatial entities while these are changing rapidly in the real world. This makes current GIS incapable of modeling dynamic spatial processes. In this paper, the development of a process-based model is described. The model is developed based on spatial system theory and the Voronoi spatial model. First, the paper discusses spatial system theory, which forms the theoretical background for the model. Second, the Voronoi spatial model is adopted to describe spatial processes; it is more efficient than conventional vector and raster models. Third, the paper presents the capabilities of the model in one application.     

一种适合掌上电脑GIS矢量的栅格存储数据结构的研究

提出了一种适应于以掌上电脑为硬件平台的GIS数据存储数据结构设计技术 ,即基于矢量的栅格化存储结构 ,该数据结构适应于以掌上电脑为代表的小型嵌入式智能移动终端图形显示。     

Basic Topological Models for Spatial Entities in 3-Dimensional Space

In recent years, models of spatial relations, especially topological relations, have attracted much attention from the GIS community. In this paper, some basic topologic models for spatial entities in both vector and raster spaces are discussed.It has been suggested that, in vector space, an open set in 1-D space may not be an open set any more in 2-D and 3-D spaces. Similarly, an open set in 2-D vector space may also not be an open set any more in 3-D vector spaces. As a result, fundamental topological concepts such as boundary and interior are not valid any more when a lower dimensional spatial entity is embedded in higher dimensional space. For example, in 2-D, a line has no interior and the line itself (not its two end-points) forms a boundary. Failure to recognize this fundamental topological property will lead to topological paradox. It has also been stated that the topological models for raster entities are different in Z ² and R ². There are different types of possible boundaries depending on the definition of adjacency or connectedness. If connectedness is not carefully defined, topological paradox may also occur. In raster space, the basic topological concept in vector space—connectedness—is implicitly inherited. This is why the topological properties of spatial entities can also be studied in raster space. Study of entities in raster (discrete) space could be a more efficient method than in vector space, as the expression of spatial entities in discrete space is more explicit than that in connected space.