Remote sensing research issues of the National Land Use Change Program of China

In 1999, the Ministry of Land and Resources (MLR) of China launched the National Land Use Change Program especially to monitor the scale and distribution of urban expansion and the decrease in cultivated land through remote sensing technology. This Program has been carried out annually and continuously for seven years since then and played an important role in the policy-making of MLR about land management and planning. This paper gives an overview about this Program and discusses several research issues. First, the remote sensing data sources and other ancillary data used in this Program are presented. The approaches for image preprocessing, i.e. radiometric normalization, image geometric rectification and image fusion are then introduced with an emphasis on the algorithm development for image registration. Second, land use change detection technique is the most critical and complex aspect of the Program. The methodologies for change detection using either bi-temporal image pair or one existing land use map and one remotely sensed image are detailed. Third, since the data of land use changes derived from remote sensing will be operationally used for local and central government, field validation and accuracy assessment are crucial to ensure the reliability of change detection results. The strategy of field work and the resulting accuracy evaluations is presented. The land use and change information derived from remotely sensed data has wide applications for land management, including land use database updating, verification of land use planning and monitoring of national high-tech parks. Last, suggestions on how to make full use of the images and change detection result, to improve the consistency of land use classification and to develop change detection algorithms for diverse and complex remote sensing data are given.     

基于ArcGIS Engine的水下间断等高线自动连接研究

本文利用ArcGIS提供的数据分析和数据管理功能对不连续的水下等高线自动连接问题进行了研究。ArcGIS Engine作为ESRI公司最新推出的面向开发的嵌入式组件,具有高效便捷的特点,由于其开发时完全脱离了ArcGIS桌面平台,因而为用户提供了一个可供选择的,有针对性的,低成本的GIS应用选择。本文对水下地形等高线的断线自动连接问题应用ArcGIS Engine进行了研究实验,阐述了使用该技术编程的具体过程,实验结果证明了本文方法的有效性和实用价值。     

Road Surface Modeling and Representation from Point Cloud Based on Fuzzy Clustering

A scheme for an automatic road surface modeling from a noisy point cloud is presented. The normal vectors of the point cloud are estimated by distance-weighted fitting of local plane. Then, an automati...     

苏通大桥钢箱梁制造几何控制三维高精度基准网测设

本文详细介绍了对苏通大桥主桥钢箱梁制造几何控制三维高精度基准网的测设，通过实际工程的实施对高精度三维基准网的方案设计和精度控制进行了有效的探索。     

Transmission and visualization of large geographical maps

Transmission and visualization of large geographical maps have become a challenging research issue in GIS applications. This paper presents an efficient and robust way to simplify large geographical maps using frame buffers and Voronoi diagrams. The topological relationships are kept during the simplification by removing the Voronoi diagram’s self-overlapped regions. With the simplified vector maps, we establish different levels of detail (LOD) models of these maps. Then we introduce a client/server architecture which integrates our out-of-core algorithm, progressive transmission and rendering scheme based on computer graphics hardware. The architecture allows the viewers to view different regions interactively at different LODs on the network. Experimental results show that our proposed scheme provides an effective way for powerful transmission and manipulation of large maps.     

Normalized algorithm for mapping and dating forest disturbances and regrowth for the United States

Forest disturbances such as harvesting, wildfire and insect infestation are critical ecosystem processes affecting the carbon cycle. Because carbon dynamics are related to time since disturbance, forest stand age that can be used as a surrogate for major clear-cut/fire disturbance information has recently been recognized as an important input to forest carbon cycle models for improving prediction accuracy. In this study, forest disturbances in the USA for the period of ∼1990–2000 were mapped using 400+ pairs of re-sampled Landsat TM/ETM scenes in 500m resolution, which were provided by the Landsat Ecosystem Disturbance Adaptive Processing System project. The detected disturbances were then separated into two five-year age groups, facilitated by Forest Inventory and Analysis (FIA) data, which was used to calculate the area of forest regeneration for each county in the USA.     

天津三维城市地质信息系统数据库建设技术要求的探讨研究

天津三维城市地质信息系统融海量数据管理、分析评价和信息发布功能为一体,是天津市地质工作信息数据维护、发布和长期动态服务于经济社会发展的基础性、综合性的平台。数据信息的统一、规范是该平台功能发挥的关键。本文从天津城市发展对地质成果信息的需求出发,提出城市地质信息系统各类专业数据库建设的技术要求,以满足系统分析评价、三维模型建立精度,实现从源头保证各类数据有序入库,终端输出的各类信息真实可信,确实为各部门提供决策依据。     

基于GPRS的嵌入式工程测量数据通信系统研究

本系统基于GPRS技术和嵌入式实时操作系统研发的一套工程测量数据无线传输平台。本文简要介绍GPRS技术和嵌入式实时操作系统，详细介绍了系统的组成，软硬件的设计方案及在工程测量中应用情况。     

房产测量中椭圆和样条曲线的多段线逼近

本文介绍了在AutoCAD环境中,对椭圆和样条曲线以面积为逼近指标调整偏移距离,用B样条函数处理偏移后样条曲线的控制数据,生成多段线逼近原椭圆或样条曲线的方法.解决了房产测量和建筑设计中将椭圆和椭圆弧精确地转化为多段线的问题.     

《江苏省地图集》电子版的设计与实现

探讨地图集电子版的设计原则,从《江苏省地图集》电子版的设计与实现入手,分析地图集电子版的设计思路和技术方案.阐述多媒体电子地图集的解决方案.