一种改进Cartographer算法的建图方法研究

对于传统激光雷达建图算法中存在的点云特征提取不完善、质量低,噪声影响导致的位姿数据偏差影响建图效果的问题,提出了一种基于改进Cartographer算法的激光建图方法。首先,在传感器信息融合部分,用自适应无损卡尔曼滤波(AUKF)的方法,对传感器数据进行预测更新,再对噪声进行自适应优化,来减小噪声对位姿数据造成的影响;其次,在处理激光雷达采集的点云数据时,改进体素滤波的效果,通过对点云赋权过滤的方法进行点云信息的二次筛选,以降低点云的冗余,提升点云质量;最后,在真实环境进行建图测试,比较改进后算法与传统算法的建图效果,在室外环境下改进算法比原算法绝对平移误差降低了25.8%,绝对旋转误差降低了28.9%。可明显看出改进算法数据误差更小,建图效果更加精确。

基于多分辨率地图位姿跳变优化的改进Cartographer算法

针对Cartographer算法在局部扫描匹配中,存在匹配精度低、位姿跳变影响回环检测的问题,提出一种基于多分辨率地图位姿跳变优化的改进Cartographer算法。首先,在局部优化中,建立多分辨率栅格地图,提高初始位姿的估计精度;然后,在回环检测和全局优化之间,建立位姿跳变检测机制,通过减少突变节点数量,提高回环检测的可靠性;最后,通过数据集中,对改进算法进行验证。结果表明:该算法能有效提高定位精度和建图效果。

基于Cartographer的智能探测机器人

设计了一种基于Cartographer的智能探测机器人系统。该系统采用一块NVIDIA Jetson Nano作为主控制器,能够执行SLAM算法以及控制机器人的各项功能。其主要硬件包括激光雷达、相机、惯性测量单元、二氧化碳传感器及烟雾探测器等,用于实时测距、地图构建、姿态估计以及视觉感知。另外还介绍了SLAM和视觉感知算法的优化和实现过程。通过这些优化,系统能够在复杂环境中实现准确的导航,其在实验测试中表现良好,为智能探测机器人领域的发展提供了一种有效的设计方案。

Mathematical Definitions of Operators for Cartographic Generalization

This paper puts forword 11 cartographic generalization operator models and introduces their mathematical definitions,and thus a precise mathematical form and quantitative description has been given to these formerly limited qualitative concepts.The meaning of mathematical definition of operators for cartographic generalization and the application prospect in computer_aided cartography (CAC) is stated.ract The Jurassic strata in Jingyan of Sichuan containing the Mamenchinsaurus fauna are dealt with and divided in this paper. The Mamenchisaurus fossils contained there are compared in morphological features and stratigraphically with other types of the genus on by one. The comprehensive analysis show that the Mamenchisaurus fauna of Jingyan appeared in the early Late Jurassic and is primitive in morphology. The results of the morphological identification and stratigraphical study agree with each other. Their evolutionary processes in different apoches of the Late Jurassic also made clear. Key words Jingyan, Sichuan, Mamenchisaurus Fauna, stratigraphy, evolution

A Fast Algorithm of Cartographic Sounding Selection

An effective strategy and framework that adequately integrate the automated and manual processes for fast cartographic sounding selection is presented. The important submarine topographic features are extracted for important soundings selection, and an improved "influence circle" algorithm is introduced for sounding selection. For automatic configuration of soundings distribution pattern, a special algorithm considering multi factors is employed. A semi automatic method for solving the ambiguous conflicts is described. On the basis of the algorithms and strategies a system named HGIS for fast cartographic sounding selection is developed and applied in Chinese Marine Safety Administration Bureau (CMSAB). The application experiments show that the system is effective and reliable. At last some conclusions and the future work are given.

基于改进Cartographer的激光SLAM算法

针对Cartographer算法在激光雷达的数据处理中存在的点云特征丢失的问题和低帧率激光雷达导致的运动畸变问题,提出一种改进激光同步定位与地图构建(simultaneous localization and mapping, SLAM)算法。采用k邻域搜索邻近点降采样的体素滤波方法代替Cartographer算法中的传统体素滤波方法,在不丢失点云特征的情况下提升计算速率;嵌入轮式里程计辅助模块去除激光雷达运动畸变,减少机器人的位姿累积误差,从而改善建图效果;最后,增加了边约束条件改善回环检测效果。通过在机器人操作系统中的gazebo搭建仿真环境进行模拟实验,对比两种算法,实验结果显示改进算法的建图轨迹误差更小。

Predicting upslope expansion of sub-alpine forest in the Makalu Barun National Park, Eastern Nepal, with a hybrid cartographic model

The natural upper boundary of a forest（forest line） in mountain environments is an indicator of climate conditions. An increase in global average temperatures has resulted in an upward advance of the forest line. This advance may result in fragmentation of the alpine ecosystem and a loss of biodiversity. Therefore, it is important to identify potential areas where current forests can advance under scenarios of future climate change. I used expert knowledge and cartographic modeling to create a hybrid cartographic model considering five topographic variables to predict areas where forest line can expand in the future.The prediction accuracy of the model is around 82%. The model is able to predict areas above the current forest line that are suitable or unsuitable for future forest advance.Further inclusion of high-resolution satellite imagery and digital elevation models, as well as field-based information into the model can help to improve the model accuracy.

GEODESY AND DIGITAL CARTOGRAPHIC SURVEY IN FILDES PENINSULA,REY JORGE ISLAND,ANTARCTICA

The present paper summarizes a joint effort undertaken by the Instituto Geográfico Militar de Chile (IGM) and the Instituto Antártico Chileno (INACH) in order to obtain digital cartography of the Fildes Peninsula, Rey Jorge Island, Antarctica. This peninsula constitutes the prototype project area for the main IGM-INACH project No 153 “Cartographic Survey and Geographic Information System of the South Shetlands Islands” The Digital Cartography was implemented at the 1:5 000 scale, using geodetic GPS control points referenced to ITRF 92 and WGS 84 Data. The UTM Projection was used. All products were produced in compliance with the cartographic standards of the IGM. This cartography was designed in order to satisfy the requirements of a Geographic Information System developed by INACH. This geo-referenced database incorporates a variety of thematic information, enabling it to support scientific investigations, environmental and multi-disciplinary studies, and other applications. As a result of this project the Instituto Geográfico Militar de Chile produced a map at 1:5 000 scale in digital format, and also a 1:10 000 topographic map, in paper format, with two editions: first edition of two charts and a second edition with one chart covering the whole project area. Chile and other countries have a number of important permanent activities in this area. These maps are designed to support several and diverse geo-spatial studies related to these activities.

ROS机器人Cartographer SLAM建图方法

文章首先介绍了ROS机器人硬件和软件平台,搭建了ROS开发环境的搭建,最后设计了ROS的Cartogra­pher SLAM算法框架,在ROS机器人的平台上进行了Cartographer建图试验,并用Rviz工具进行观测。

The International Cartographic Association National Atlas Commission Meeting Held in Beijing

ICA National Atlas Commission held a commission meeting and symposium from August 8-12,1990 in Beijing.Among those present at the meeting were Dr.B.Rystedt(Sweden),Chairman of ICA,Dr.E.Ciekirska(Canada),Vice Chairman of ICA and members from U.S.A.,China,Spain,the Netherlands,Czechoslovakia,India as well as representatives from U.S.S.R.,Czechoslovakia,and Spain.40 Chinese cartographers attended the meeting.The major topics

Information Theory of Cartography:An Information-theoretic Framework for Cartographic Communication

Map is one of the communication means created by human being.Cartographers have been making efforts on the comparison of maps to natural languages so as to establish a"cartographic language"or"map language".One of such efforts is to adopt the Shannon’s Information Theory originated in digital communication into cartography so as to establish an entropy-based cartographic communication theory.However,success has been very limited although research work had started as early as the mid-1960 s.It is then found that the bottleneck problem was the lack of appropriate measures for the spatial(configurational)information of(graphic and image)maps,as the classic Shannon entropy is only capable of characterizing statistical information but fails to capture the configurational information of(graphic and image)maps.Fortunately,after over 40-year development,some bottleneck problems have been solved.More precisely,generalized Shannon entropies for metric and thematic information of(graphic)maps have been developed and the first feasible solution for computing the Boltzmann entropy of image maps has been invented,which is capable of measuring the spatial information of not only numerical images but also categorical maps.With such progress,it is now feasible to build the"Information Theory of Cartography".In this paper,a framework for such a theory is proposed and some key issues are identified.For these issues,some have already been tackled while others still need efforts.As a result,a research agenda is set for future action.After all these issues are tackled,the theory will become matured so as to become a theoretic basis of cartography.It is expected that the Information Theory of Cartography will play an increasingly important role in the discipline of cartography because more and more researchers have advocated that information is more fundamental than matter and energy.

A COMPARATIVE STUDY ON THE CARTOGRAPHIC HISTORIES BETWEEN CHINA AND THE WEST

Analysis of space shifting of geodetic center of China and the West,reveals that the China's geodetic center has been in coincidence with its political center. Furthermore the development of the maps in Europe was controlled by developmat of economy. Thereupon, maps in China and the West were developing in their own ways, and thus formed two different cartographic systems.Although China has a splendid cartogrphic history, it has not yet got many great breakthroughs. The reasons are as follows : 1. The theory of round earth has never occupied the ruling place, instead, the theory of flat earth took the dominant position. Thus the geodetic frameworks of China are not scientific. 2. Owing to the trammels of the theory that China is the whole earth, the Chinese geodetic workers have been limited in China's area. 3. Exchange between the East and the Weat is too late. The Chinese geodetic workers took a long time to accept the West geodetic technology. on the contrary, the West has absorbed the geodetic technology and results of China. 4. China's anciat gcodotic workers usually stopped after getting a little knowledge of a subject. They should have made great breakthroughs in geodetic area. Nevertheless, they failed.

State of Cartographic Services among the East African Community Member States

The East African Community is a regional block that brings together Kenya, Uganda, Tanzania, Rwanda, Burundi and South Sudan into various forms of economic partnership, the eventual dream being to achieve political federation. The current activities within this community, plus the block’s further development, require the generation and sharing of much geo-information to support the attendant decision-making. Such geo-information can be best served through a harmonized cartographic service with common standards. Such a harmonized service is not only lacking, but even the status of the current national services is also largely unknown. This paper reports on a study undertaken to establish this status, as represented by twelve elements of a cartographic service that the authors are able to establish. Results of the study have shown that the present national services are characterized by inadequate basic datasets that remain largely analogue. In addition, there are non-uniform spatial reference systems, inadequate cartographic human resources and lack of common mapping standards;further, funding for mapping activities remains low in national budgets. Given that over 80% of decisions are influenced by geo-spatial data, these findings point to an urgent need to improve, harmonize and digitize these services as the way forward, if the East African Community is to remain globally competitive.

Location Based Navigation Service Technology: Development of an Optimization Algorithm for Multivariate Contextual Cartographic Content in Location Based Navigation Service

User response or reaction to navigation applications is influenced by relevance in geographic information, in terms of cartographic context and content delivered within a definite time, providing a direct impact to outcome or consequence based on decision making and hence user reaction. Location Based Navigation Services (LBNS) have continuously advanced in cartographic visualization, making maps interpretation easy and ubiquitous to any user, as compared to pre-historic times when maps were a preserve of a few. Despite rapid growth in LBNS, there exist challenges that may be characterized as technical and non-technical challenges, among them being process of conveying geospatial information to user. LBNS system deliver appropriate information to a user through smartphone (mobile device) for effective decision making and response within a given time span. This research focuses on optimization of cartographic content for contextual information in LBNS to users, based on prevailing circumstances of various components that constitute it. The research looks into Geographic Information Retrieval (GIR), as a technical challenge centered on a non-technical issue of social being of user satisfaction, leading to decision making in LBNS, hence response and outcome. Though advanced technologically, current LBNS on information sourcing depends on user manual web pages navigation and maneuver, this can be painstaking and time consuming that it may cause unnecessary delay in information delivery, resulting to delayed information response time (DIRT). This in turn may lead to unappropriate decision making with erroneous reaction or response being taken, resulting in loss of opportunity, resources, time and even life. Optimization in LBNS is achieved by a mathematical relationship developed between user status, mobile device variables against cartographic content. The relationship is in turn applied in LBNS android application to fulfill optimization solution for user consumption.

基于位姿阈值的Cartographer SLAM算法实验设计

针对Cartographer算法回环检测耗时、实时性差的问题,采用软硬件结合的方式,设计了一种基于位姿阈值的Cartographer SLAM算法实验。依托Clearpath Jackal无人车和ROS软件操作系统,搭建了实验硬件平台,采用Cartographer SLAM和位姿阈值优化算法设计了软件操作流程。实验结果表明,Cartographer SLAM算法可获取无人车实时位姿,构建清晰的实验室地图;位姿阈值优化算法有效地剔除了回环检测时的冗余信息,提升了计算效率和实时性。该实验加深了学生对Cartographer SLAM算法的认知,激发了学生对无人车及人工智能等技术的学习兴趣,提高了学生的工程实践能力和创新能力。

Applying Digital Image Processing to Evaluate a Extraction Method of Cartographic Features in Digital Images

A topic studied in cartography is to make the extraction of cartographic features that provide the update of cartographic maps more easily. For this reason many automatic routines were created with the intent to perform the features extraction. Despite of all studies about this, some features cannot be found by the algorithm or it can extract some pixels unduly. So the current article aims to show the results with the software development that uses the original and reference image to calculate some statistics about the extraction process. Furthermore, the calculated statistics can be used to evaluate the extraction process.

A STUDY ON THE CARTOGRAPHIC FUZZY MATRIX MODEL AND MATHEMATICAL EXPRESSIONS OF CARTOGRAPHIC TERMS

On the basis of the research of the cartographic modelsmade by the authors some years ago,this paper further studies theestablishment of cartographic fuzzy matrix to make the concepts incartography e.g.,selection,deletion,mapping generalization andimage tranformation,into some precise mathematical expressions.

基于图顶点深度聚类的建筑物合并方法

建筑物要素合并是大比例尺地图缩编过程中实现空间结构简化的重要手段。基于综合规则的合并方法难以同时顾及要素形态、分布等诸多特征,受预设算法参数影响大,综合过程缺乏灵活性。针对这一问题,本文提出了一种基于图顶点深度聚类网络的建筑物合并模型,利用Delaunay三角网构建建筑物群组表征图模型,结合自编码器与图卷积网络学习剖分三角形的几何形态、空间分布特征,采用自监督学习方式实现三角形的聚类与分类(保留、删除),最终在不依赖样本条件下实现建筑物要素端到端智能化合并。试验表明,该方法对预设合并参数依赖低,能同时顾及建筑物要素的形态与分布特征。合并过程具有一定灵活性,合并结果能较好满足地图可视化要求。

移动机器人2D激光SLAM算法仿真与实现

随着无人驾驶技术的迅速发展,同步定位与建图技术因其精度高、稳定性好的优点备受人们关注。基于激光雷达传感器,选择主流的Gmapping和Cartographer算法,搭建实验环境,对两种算法进行对比仿真与实验建图,并对两种算法的建图效果进行深度的分析。基于滤波器的Gmapping算法计算量小,依赖于里程计信息,适用于小尺度、低特征环境中;基于图优化的Cartographer算法累计误差低,精度高,适用于精度和稳定性要求较高的场合。