Automatically Conflating Road Vector Data with Orthoimagery

Recent growth of the geospatial information on the web has made it possible to easily access a wide variety of spatial data. The ability to combine various sets of geospatial data into a single composite dataset has been one of central issues of modern geographic information processing. By conflating diverse spatial datasets, one can support a rich set of queries that could have not been answered given any of these sets in isolation. However, automatically conflating geospatial data from different data sources remains a challenging task. This is because geospatial data obtained from various data sources may have different projections, different accuracy levels and different formats (e.g., raster or vector format), thus resulting in various positional inconsistencies. Most of the existing algorithms only deal with vector to vector data conflation or require human intervention to accomplish vector data to imagery conflation. In this paper, we describe a novel geospatial data fusion approach, named AMS-Conflation, which achieves automatic vector to imagery conflation. We describe an efficient technique to automatically generate control point pairs from the orthoimagery and vector data by exploiting the information from the vector data to perform localized image processing on the orthoimagery. We also evaluate a filtering technique to automatically eliminate inaccurate pairs from the generated control points. We show that these conflation techniques can automatically align the roads in orthoimagery, such that 75% of the conflated roads are within 3.6 meters from the real road axes compared to 35% for the original vector data for partial areas of the county of St. Louis, MO.

Automatic and Accurate Extraction of Road Intersections from Raster Maps

Since maps are widely available for many areas around the globe, they provide a valuable resource to help understand other geospatial sources such as to identify roads or to annotate buildings in imagery. To utilize the maps for understanding other geospatial sources, one of the most valuable types of information we need from the map is the road network, because the roads are common features used across different geospatial data sets. Specifically, the set of road intersections of the map provides key information about the road network, which includes the location of the road junctions, the number of roads that meet at the intersections (i.e., connectivity), and the orientations of these roads. The set of road intersections helps to identify roads on imagery by serving as initial seed templates to locate road pixels. Moreover, a conflation system can use the road intersections as reference features (i.e., control point set) to align the map with other geospatial sources, such as aerial imagery or vector data. In this paper, we present a framework for automatically and accurately extracting road intersections from raster maps. Identifying the road intersections is difficult because raster maps typically contain much information such as roads, symbols, characters, or even contour lines. We combine a variety of image processing and graphics recognition methods to automatically separate roads from the raster map and then extract the road intersections. The extracted information includes a set of road intersection positions, the road connectivity, and road orientations. For the problem of road intersection extraction, our approach achieves over 95% precision (correctness) with over 75% recall (completeness) on average on a set of 70 raster maps from a variety of sources.

Raster to Vector Conversion for Engineering Drawings： Survey and Prospect

1 Introduction Raster to Vector Conversion (RVC) for Engineering Drawings(ED), also known as vectorization, is a procedure to find the vector form of graphic primitives – straight line, circle and arc segments – from the raster engineering drawing. It is an automated process of analyzing and recognizing graphic primitives in the raster engineering drawing, converting them into vector form. A lot of instances need to accomplish the raster to vector recognition and conversion, for example,…     

专题图件编辑软件开发中的MapObjects技术

专题图件编辑软件主要解决栅格数据和矢量数据的叠加匹配、地图信息的分类显示以及矢量信息的物理逻辑结构转换。该文以专题图件编辑软件的部分开发过程为例,总结ESRI公司推出的GIS组件——Mapobjects在开发过程中三项关键技术的应用,为应用MapObjects进行二次开发提供一定参考。     

专题图件编辑软件开发中的MapObjects技术

专题图件编辑软件主要解决栅格数据和矢量数据的叠加匹配、地图信息的分类显示以及矢量信息的物理逻辑结构转换。该文以专题图件编辑软件的部分开发过程为例,总结ESRI公司推出的GIS组件——MapObjects在开发过程中三项关键技术的应用,为应用MapObjects进行二次开发提供一定参考。     

一种基于点模式的指纹分阶段匹配算法的研究

介绍了一个指纹中心点定位（Core）以及用中心点为中心构造特征向量进行初匹配，并且以此作为最佳匹配参考点来进行二次匹配的算法。本算法的特点：1．介绍指纹中心点的准确定位。2．以中心点作为最佳匹配参考点将匹配分为两步进行：初匹配利用了细节点间的结构关系，克服了图像的平移和旋转的影响；二次匹配引用了界限盒思想，增强指纹匹配算法对形变的适应能力。本算法把点模式的优点和基于结构的特征点之间的相对距离不变性、所跨越纹线数目的不变性、特征点类型的不变性很好结合起来。实验结果显示本算法具有较强的适应性和较高的拒识率。     

分布式空间数据库的研究与设计

对分布式空间数据库进行了分析;设计了一个分布式空间数据库的体系结构,结合空间数据的特征和GIS应用,设计了空间数据的分割和分布方法;在上面的设计基础上,提出了一个两级空间数据查询描述规范,并对分布式查询进行了设计。     

支撑向量机及其在数据挖掘中的应用

首先介绍了数据挖掘的基本概念,然后系统地研究了支撑向量机学习算法,着重分析了支撑向量机的算法的特点。并阐述了支撑向量机的关键技术一核函数。最后讨论了支撑向量中学习算法在数据挖掘中的应用。     

矢量与栅格结合的三维地质模型编辑方法

三维地质模型主要通过剖面构造．自动建模方法要求这些剖面基本平行,并且相邻剖面地质体的差别不能过大．本文针对剖面数据较少且不平行的情形,设计了人机交互的三维地质模型构造方法,利用普通多面体栅格化算法和由Marching Cubes算法得到的光栅矢量化,实现了光栅和矢量模型的相互转换．在保证模型间拓扑正确的基础上,提高了地质模型的编辑效率,并在实践中得到了检验．     

Stability of a vector integer quadratic programming problem with respect to vector criterion and constraints

The paper analyzes five types of stability against perturbations of initial data in criterion functions and constraints of vector integer quadratic optimization problems. Necessary and sufficient conditions are proved for all the types of stability. The relationship among stability with respect to changes of vector criterion coefficients, stability with respect to changes of initial data in constraints, and stability with respect to vector criterion and constraints is established. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 63–72, September–October 2006.     

Some multiclass Fisher feature selection algorithms and their comparison with Karhunen-Loève algorithms

The feature selection problem as a task of a transformation of an initial pattern space into a new space, optimal with respect to the discriminatory features is described. Transformation optimizations are realized according to the measures which may be included in the broadly understood group of Fisher measures. In particular, the use of some conception of interclass scatter matrix calculation allows us to obtain different variations of many-class Fisher measures. Finally, a theoretical comparison of some properties of the suggested Fisher transformations with other transformations based on the Karhunen-Loève expansion is presented.     

Design and realization of ad-hoc VoIP with embedded p-SIP server

In this paper we design and implement the pseudo session initiation protocol (p-SIP) server embedded in each mobile node to provide the ad-hoc voice over Internet protocol (VoIP) services. The implemented p-SIP server, being compatible with common VoIP user agents, integrates the standard SIP protocol with SIP presence to handle SIP signaling and discovery mechanism in the ad-hoc VoIP networks. The ad-hoc VoIP signaling and voice traffic performances are analyzed using E-model R rating value for up to six hops in the implemented test-bed. We also conduct the interference experiments to imitate the practical ad-hoc VoIP environment. The analyzed results demonstrate the realization of ad-hoc VoIP services by using p-SIP server.