A Location Aware Mobile Tool for Direct and Indirect Climate Data Sensors

Access to GIS data from mobile platforms continues to be a challenge and there is a wide range of fields where it is extremely useful. In this work, we combined three key aspects: climate data sensors, mobile platforms and spatial proximity operations. We published and made use of a web 2.0 network of climate data, where content is user‐collected, by means of their meteorological stations, and exposed as available information for the virtual community. Moreover, we enriched this data by giving the users the opportunity to directly inform the system with different climate measures. In general, management of this type of information from a mobile application could result in an important decision tool, as it enables us to provide climate‐related data according to a context and a geographical location. Therefore, we implemented a native mobile application for iPhone and iPad platforms by using ArcGIS SDK for iOS and by integrating a series of ArcGIS webmaps, which allows us to perform geospatial queries based on the user's location, offering, at the same time, access to all the data provided by the climate data sensor network and from direct users.     

基于Google Map技术的移动LBS应用

利用Google Map在Android移动设备上的SDK进行LBS应用系统的设计,通过对网络模块、地图模块等核心模块的构建和外接服务的嵌入,实现对当前移动互联网中移动LBS热点应用的设计原型的探讨。     

移动测量技术及其应用

讨论了全球导航卫星系统（global navigation satellite system,GNSS）/里程计（odometer,ODO）/惯性导航系统（inertial navigation system,INS）组合定位定姿中误差校正与ODO/INS组合导航两个方面的问题。针对里程计刻度因子和安装误差角的校正,在不改变原GNSS/INS滤波器的基础上,设计了GNSS/INS与INS/ODO两级卡尔曼滤波器级联结构,将INS导航误差与里程计刻度因子误差、安装误差角分别列入两个滤波器的系统状态中,在GNSS连续观测和固定模糊度条件下,利用里程计和惯导里程增量之差作为INS/ODO卡尔曼滤波器的外部观测,对误差进行校正。另一方面,使用校正过的里程计和安装误差角,在GNSS失锁条件下对INS进行观测和修正。跑车实验结果表明,本文算法可以有效校正里程计刻度因子和定位定姿（positioning and orientaton system,POS）安装误差角,同时大幅提高GNSS失锁条件下的定位精度,配合平滑卡尔曼滤波器,可将城市移动测量两分钟GNSS失锁条件下的定位误差控制在0.5 m以内。     

移动测量技术及其应用

从地理空间信息服务的关键技术与要求入手,论述了地理空间数据在地理空间信息服务的作用。在对地理空间数据采集与更新技术的分析基础上,提出了基于移动测量技术的地理空间信息服务数据采集与更新的技术途径,结合LD2000-RM移动测量系统,对其应用的领域和方向进行了介绍,最后对移动测量技术在地理空间信息服务的前景进行了展望。     

移动GIS及其新应用

本文主要说明了移动GIS的结构以及将移动GIS技术、空间定位技术和网络通信技术结合的LBS服务。并介绍了移动GIS近年来在城市导游系统,森林火灾抢险,城市救护管理系统等多个领域的新应用,总结和预见了移动GIS的发展趋势。     

Automated Production of Schematic Maps for Mobile Applications

The advent of high‐end miniature technology, together with the increasing availability of large scale digital geographic data products, has created a demand for techniques and methodologies that assist in the automated generation of maps specifically tailored to mobile GIS applications. This paper concerns itself with the problem of automatic generation of schematic maps. Schematic maps are diagrammatic representations based on linear abstractions of networks. In the context of mobile mapping they are seen as being a particularly useful means of displaying transportation networks. This paper describes an algorithm that automates the production of schematic maps. The algorithm makes use of the simulated annealing optimisation technique. An implementation of the algorithm is also presented, together with experimental results.     

基于SuperMap iMobile的移动GIS产品与应用

首先介绍了移动GIS包括更好用户体验、服务式GIS、支持服务聚合能力、支持移动端三维GIS等发展趋势,接着介绍了超图软件移动GIS产品对内容可定制与移动任务管理、终端群组数据与位置协同、移动终端监控、多源数据接入、离线与在线结合、GIS与导航结合、二三维一体化支持、多平台支持等特点;并以SuperMap Field-Mapper为例,介绍了SuperMap移动GIS在应急救灾中的典型应用。     

基于移动终端的地理信息核查技术应用研究

传统的航测外业调绘基本上是基于纸质调绘片的作业模式,这种外业调绘模式容易造成工作的重复、调绘信息的遗漏以及内外业衔接矛盾等问题,在一定程度上影响了航测数据的生产效率。为有效解决上述问题,建立一种全新的外业调绘模式,本文对基于移动终端的地理信息核查技术进行研究,实现了外业调绘成果的快速、高效采集以及内业和外业的一体化衔接,提高了的航测生产效率,实现了"内外一体"的信息化测绘生产体系。     

空地协同移动智能服务平台研发及典型应用

面向万物互联时代的移动智能服务需求,亟须建立空地协同智能服务平台。由于核心设备和算法的限制,空地协同移动智能服务平台发展较为缓慢。由此通过攻关传感器实时位置和姿态测量的核心技术与数据处理和分析的关键算法,研制了高精度位姿测量设备,研发了机载和车载空地多平台协同组网遥感观测系统,实现了多源遥感影像质量改善与智能精处理,有效支撑遥感测绘服务,提升遥感信息自动化处理水平,从而解决了空地协同智能服务平台中“准、快、灵”的难题,实现“北斗+位姿测量仪”全球自主“定基准”、空地协同组网快速“找目标”、智能化精处理自动“查变化”。成果已被广泛应用于地理国情监测、智慧城市规划和建设、应急测绘保障等行业。     

A Web-Based Java Framework for Cross-Platform Mobile GIS and Remote Sensing Applications

A cross-platform Web-based Java development framework for Mobile Geographic Information Systems (Mobile GIS) and remote sensing (RS) applications is introduced for the notebook computer, Pocket PC, and mobile phone platforms. Using these platforms, Java software technology is examined for its crossplatform utility in the development of various Mobile GIS and map/image display functions. The three case studies developed with Java 2 Standard Edition (J2SE), Java 2 Micro Edition (J2ME), and Mobile Information Device Profile (MIDP) are examined within the context of mobile GIS. Significant challenges in developing cross-platform Mobile GIS applications are also discussed. These obstacles include heterogeneous operating systems, different wireless communications protocols, lowbandwidth network connections, and the general lack of usability.     

Spatially convergent GPS kinematic positioning

It is a known fact that obtaining accurate GPS carrier-phase measurements involves fixed, unknown whole-cycle ambiguity parameters. As the use of cosine functions to eliminate any double-difference integer ambiguities causes spatial ambiguity problems, both reasonably approximated positions and wavelength-dependent convergence ranges are of the utmost importance. Differential GPS-based position solutions are first smoothed to create a polynomial trajectory, leading to less variable position approximations. Long-wavelength wide-lane phase combinations will then be utilized to facilitate convergent GPS positioning, on a stage-by-stage basis. Although double-difference ionospheric path delays are often interpreted as nuisance parameters, they can be obtained when the respective cosines of the original L1 and L2 carrier phases undergo a simultaneous least-squares estimation. In particular, quadratic forms of the estimated phase residuals will be linked with hypothesis testing to allow for a meaningful statistical inference. Some low-dynamics experiments are then performed to prove the feasibility of the proposed hierarchical positioning concept. Electronic Publication     

面向移动互联网应用的全景地图切片技术研究

针对移动互联网现有硬件性能不足的情况,提出了一种全景地图切片技术。首先将全景图投影到立方体的六个面上,然后分级裁切全景图,形成多级切片金字塔。通过实际应用证明,该技术能够有效提高全景图的加载显示速度,很好地满足了移动互联网的应用需要。     

GeoJabber: Enabling Geo-Collaborative Visual Analysis

The GeoJabber concept, protocol, and working prototype software introduced here enable same-time, different-place collaborative geovisualization. The key problem this work addresses is how to turn geovisual software states into persistent textual representations that can be shared between users. In the current implementation, GeoJabber leverages three key Open Source technologies: the GeoViz Toolkit, the Jabber protocol, and XStream. GeoJabber is the first project to support same-time different-place geovisualization tool state sharing. As part of this effort, this paper presents a typology of sharable geovisualization software states, rooted in the concepts of data, display, and category.     

The Influence of Digital Surface Model Choice on Visibility‐based Mobile Geospatial Applications

In this work we investigate the effectiveness of different types of visibility models for use within location‐based services. This article outlines the methodology and results for our experiments, which were designed to understand the accuracy and effects of model choices for mobile visibility querying. Harnessing a novel mobile media consumption and authoring application called Zapp, the levels of accuracy of various digital surface representations used by a line of sight visibility algorithm are extensively examined by statistically assessing randomly sampled viewing sites across the 1 km² study area, in relation to points of interest (POI) across the University of Nottingham campus. Testing was carried out on three different surface models derived from 0.5 m LiDAR data by visiting physical sites on each surface model with 14 random point of interest masks being viewed from between 10 and 16 different locations, totalling 190 data points. Each site was ground‐truthed by determining whether a given POI could be seen by the user and could also be identified by the mobile device. Our experiments in a semi‐urban area show that choice of surface model has important implications for mobile applications that utilize visibility in geospatial query operations.     

Spatially constrained regionalization with multilayer perceptron

In this article, multilayer perceptron (MLP) network models with spatial constraints are proposed for regionalization of geostatistical point data based on multivariate homogeneity measures. The study focuses on non‐stationarity and autocorrelation in spatial data. Supervised MLP machine learning algorithms with spatial constraints have been implemented and tested on a point dataset. MLP spatially weighted classification models and an MLP contiguity‐constrained classification model are developed to conduct spatially constrained regionalization. The proposed methods have been tested with an attribute‐rich point dataset of geological surveys in Ukraine. The experiments show that consideration of the spatial effects, such as the use of spatial attributes and their respective whitening, improve the output of regionalization. It is also shown that spatial sorting used to preserve spatial contiguity leads to improved regionalization performance.     

Temporal Interpolation of Spatially Dynamic Polygons

In this study we compare two methods of interpolating simple metrics from polygons that change over time. Conventional methodology involves computing values of the metrics at points in time where the polygon is observed, and interpolating between these observed values to estimate values at other points in time. An alternative method applies interpolation techniques to the locations of vertices composing polygons are interpolated between observations and metrics are computed from the interpolated polygon shapes. We conducted a Monte Carlo simulation of both techniques using simulated polygons composed of varying numbers of vertices, which were allowed to move randomly over varying numbers of discrete time periods. We observed differences in the success of the two methods when applied to three metrics: Area, Perimeter, and Area/Perimeter Ratio. We found the two techniques to perform differently depending upon the metric being interpolated. Full results are presented and possible reasons why the techniques succeeded or failed under various conditions are discussed.     

浅析移动计算、移动GIS与移动数据库

分析了移动计算、移动GIS和移动数据库的概念和特点,剖析三者之间的联系,以宏观的视角思考基于此新技术框架下的空间应用,基于电子地图实践,归纳并提出改进空间信息服务可行性建议。     

Spatially weighted supervised classification for remote sensing

A simple approach for incorporating a spatial weighting into a supervised classifier for remote sensing applications is presented. The classifier modifies the feature-space distance-based metric with a spatial weighting. This is facilitated by the use of a non-parametric (k-nearest neighbour, k-NN) classifier in which the spatial location of each pixel in the training data set is known and available for analysis. A remotely sensed image was simulated using a combined Boolean and geostatistical unconditional simulation approach. This simulated image comprised four wavebands and represented three classes: Managed Grassland, Woodland and Rough Grassland. This image was then used to evaluate the spatially weighted classifier. The latter resulted in modest increase in the accuracy of classification over the original k-NN approach. Two spatial distance metrics were evaluated: the non-centred covariance and a simple inverse distance weighting. The inverse distance weighting resulted in the greatest increase in accuracy in this case.     

Spatially simplified scatterplots for large raster datasets

Abstract

Scatterplots are essential tools for data exploration. However, this tool poorly scales with data-size, with overplotting and excessive delay being the main problems. Generalization methods in the attribute domain focus on visual manipulations, but do not take into account the inherent nature of information redundancy in most geographic data. These methods may also result in alterations of statistical properties of data. Recent developments in spatial statistics, particularly the formulation of effective sample size and the fast approximation of the eigenvalues of a spatial weights matrix, make it possible to assess the information content of a georeferenced data-set, which can serve as the basis for resampling such data. Experiments with both simulated data and actual remotely sensed data show that an equivalent scatterplot consisting of point clouds and fitted lines can be produced from a small subset extracted from a parent georeferenced data-set through spatial resampling. The spatially simplified data subset also maintains key statistical properties as well as the geographic coverage of the original data.