2004年以来青海湖快速扩张对人居设施与草地的潜在影响

作为我国最大的内陆咸水湖,青海湖是青藏高原东北部重要水汽源,在维持区域生态环境及半干旱生态系统功能方面发挥着重要作用.近年来,青海湖水位迅速上升,但是湖泊扩张对周边人居设施与草地的影响尚未得到广泛关注和报道.基于1995-2019年Landsat TM/ETM+/OLI遥感影像、Hydroweb多源测高同化水位数据、S...     

铣刨机在高速公路养护维修工程中的应用

近年来高等级公路正在我国迅速发展,养护与维修路面是一项迫切任务。以2000 DC型铣刨机为例介绍其在维修路面中的作用,以及这种铣刨机的结构、技术参数、主要性能及现场应用注意事项。     

利用GPS公路网数据进行影像纠正

结合国家1：50000数据库更新工程中影像正射纠正的需要,充分利用GPS公路网数据作为控制源,结合控制点和控制线混合的广义点光束法区域网平差策略和算法．实现遥感影像的快速正射纠正,避免或减少了外业控制点的采集。经过分析两个试验区的正射纠正检查精度,基本上可以满足1：50000比例尺正射影像的生产需要。     

湖南省公路交通网络可达性研究

本文以ArcGIS软件的空间网络分析模块为主要技术手段,采用加权平均旅行时间为主要指标,对不同阶段湖南省区域的公路交通网络可达性进行定量测度与分析。研究表明,20世纪80年代以来湖南省可达性水平由长株潭地区为中心向外围呈圈层式优化之势,可达性值变化率呈多级格局,可为进一步优化区域交通网络提供参考。     

道路地图示意性表达的可用性评估

当前示意性地图表达主要针对公共交通网络,缺乏对道路地图示意性表达可用性评估研究。本文选取景区和街道两个典型道路场景,采用最新的自动示意化方法生成示意地图,以主观问卷调查结合客观眼动试验的方式,评估道路地图示意性表达的可用性。试验结果表明:①示意性表达能够提升道路地图的简化度、清晰度及用户满意度,尤其对于原始道路形状较为复杂的情况;②示意地图中路径形状简化会造成不同路径感知长度差异的改变,从而影响到人们路径抉择行为;③对于路径示意性结果增加了道路网密集程度的情况,会降低示意地图认知效率。本文研究成果有助于道路地图自动示意性表达规则完善和方法优化,能够进一步提升地图示意性表达的实用性。     

利用浮动车GPS轨迹识别与提取城市道路交叉口

道路交叉口作为道路交汇的枢纽,是路网的重要组成部分,也是最重要的基础地理信息数据之一.浮动车GPS数据具有易获取、低成本和数据量大等优点,但工作同时伴随不少噪点.为了降低噪点对交叉口提取过程的影响,提高计算效率,本文运用KNN算法建立空间索引;计算向量夹角,判定道路出入口,粗筛取交叉口附近点;分别采用K-means算法...     

Fuzzy Logic System for Road Identification Using Ikonos Images

Research into both extraction of man-made objects and automatic change detection from aerial and satellite images has made significant progress in recent years. This paper presents an approach, based on a fuzzy logic system, for the identification of suburban roads in Ikonos images. The linguistic variables are the mean and standard deviation (SD) of different objects with Gaussian membership function. After the roads have been identified provisionally and their skeleton extracted, the skeleton can be vectorised and then used as direct input to a GIS for further analysis. The method was tested on an Ikonos "Geo" image covering Bilesavar in north-western Iran. For the suburban area of Bilesavar, the results showed that grey scale values ranged from 20 to 190 for non-roads and 226 to 228 for roads, the optimum width of the Gaussian kernel function was 3 and the SD was 0.4. It was also found that about 91% of main roads with a width of 6 to 12 pixels could be extracted from high resolution satellite imagery by the algorithm. The computer program for this study has been developed in visual C++ based on Windows 98     

基于遥感影像的地图道路网数据变化检测研究

在遥感影像和地图道路网数据精确配准的基础上,提出了利用缓冲区约束下的、基于知识判断的多尺度模板匹配方法检测变化的道路,对旧地图中的道路变化情况自动检测;采用自动赋初值的LSB-Snake模型半自动检测新增道路。实验表明,所提出的方法可以有效地检测道路变化,达到较高的自动化程度。     

3D information extraction from laser point clouds covering complex road junctions

An automated method for 3D modelling of complex highway interchanges is presented. Laser data and 2D topographic map data have been combined in an innovative 3D reconstruction procedure. Complex situations as shown in this paper demand knowledge to guide the automatic reconstruction. This knowledge has been used in the fusion procedure to constrain the topological and geometrical properties of the reconstructed 3D model. These additions are needed to take care of the lack of data in occluded areas. Laser data has been segmented and filtered before it is fused with map data. In the surface-growing algorithm combining map and laser points, the laser data is assigned to the corresponding road element. Although results are shown using two specific data sources, the algorithm is designed to be capable of dealing with any polygon-based topographic map and any aerial laser scanner data-set.