MAPGIS大比例尺数字测图系统的设计

随着城市信息化建设特别是GIS应用的发展，对大比例尺数字图的需求日益增加。以往的测图软件往往着重于制图的需要，很少考虑GIS应用的需求。在MAPGIS平台的基础上，根据系统性、兼容性、扩展性和开发性等原则，详细探讨了大比例尺数字测图系统的整体结构、数据组织、工作流程，设计了一个完整的数字测图系统。该系统具有野外数据采集、输入、处理、联接成图、编辑与修改及绘图等淡啤酒，在输入地物图形的同时，可以输入图形属性信息，输出符合国家标准图式的图形，并自动生成和维护拓扑关系。输出成果数据可以直接进入GIS系统，进行分析处理。     

成都盆地南缘与新构造运动有关的河道演变及其对沉积作用影响初步探讨

本文利用2002年的ETM＋图像和该地区1：25万DEM数据,采用计算机图像处理和目视解译相结合的方法,辅以野外实测数据、历史资料进行综合分析,对该地区河道的演变特征和新构造进行详细解译。基本查清了新近系以来该地区河道的发展演变历程,岷江和青衣江都存在很大幅度的河道迁移现象,综合研究发现,河道迁移与该地区新构造运动密切相关。     

Spheroidal equal angular DEMs: The specificity of morphometric treatment

Digital elevation models (DEMs) are commonly constructed using two main types of regular grids: plane square grids and spheroidal equal angular grids. Methods and algorithms intended for plane square‐gridded DEMs should not be directly applied to spheroidal equal angular DEMs. This is because these grids have fundamentally different geometry. However, some researchers continue to apply square‐grid algorithms to spheroidal equal angular DEMs. It seems appropriate to consider once again the specifity of morphometric treatment of spheroidal equal angular DEMs. This article, first, demonstrates possibilities of direct calculation of local, nonlocal, and combined morphometric variables from spheroidal equal angular DEMs exemplified by slope gradient, catchment area, and topographic index. Second, the article shows computational errors when algorithms for plane square‐gridded DEMs are unreasonably applied to spheroidal equal angular DEMs. The study is exemplified by two DEMs. A medium‐resolution DEM of a relatively small, high‐mountainous area (Mount Elbrus) was extracted from the SRTM1 DEM. A low‐resolution DEM of a vast region with the diverse topography (the central and western regions of Kenya) was extracted from the SRTM30_PLUS DEM. The results show that application of square‐grid methods to spheroidal equal angular DEMs leads to substantial computational errors in models of morphometric variables.     

遥感蚀变信息检测中背景与干扰问题研究

在不同自然景观区的遥感蚀变信息检测中,背景与干扰是2个复杂而又容易混淆的研究对象。本文结合光谱混合模型理论与随机变量概率分布相关理论,深入分析了遥感数据的光谱空间几何结构特征(重点剖析二维散点图),系统研究了背景与干扰的关系、复杂度以及干扰地物类型的划分等问题。这些问题的探讨为遥感蚀变信息检测的最佳方案设计和蚀变信息潜在性评价与准确提取提供了技术思路。     

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导航电子地图增量更新服务及关键技术研究

以移动通讯数据传输技术、网络技术和时态数据库技术为基础,构建了导航地理信息的变化发现、分析甄别、采集、加工、处理、存储和发布服务一体化的增量式更新服务模式、技术、软件、质检和标准体系,论述了多源数据融合、时空模型及空间关系的动态实时维护、多尺度增量式导航电子地图综合处理、路径规划和质检方法等关键性技术,实现了导航电子地图近实时更新服务。     

真三维立体显示技术在不动产登记统一平台中的应用研究

随着国家不动产统一登记制度的实施,城市房屋、林地、草原、土地等不动产统一整合、调查和管理工作迫在眉睫。基于机载多角度倾斜摄影和激光雷达扫描技术的创新,真三维数据可为不动产登记提供真实统一、高精度、多层次的空间载体,保证了城市不动产登记应用创新和制度创新。     

关于地籍工作底图获取方法的探讨

随着社会的发展,现代地籍因其保护土地产权与课税服务的特性越来越被人们重视,成为国土资源管理、城市建设管理的有力依据。本文初步探讨了几种地籍工作底图制作的作业流程、适用工作范围及其优缺点,并简要介绍了新技术在地籍工作底图中的应用。     

2-D delineation of individual citrus trees from UAV-based dense photogrammetric surface models

One of the challenges of remote sensing and computer vision lies in the three-dimensional (3-D) reconstruction of individual trees by using automated methods through very high-resolution (VHR) data sets. However, a successful and complete 3-D reconstruction relies on precise delineation of the trees in two dimensions. In this paper, we present an original approach to detect and delineate citrus trees using unmanned aerial vehicles based on photogrammetric digital surface models (DSMs). The symmetry of the citrus trees in a DSM is handled by an orientation-based radial symmetry transform which is computed in a unique way. Next, we propose an efficient strategy to accurately build influence regions of each tree, and then we delineate individual citrus trees through active contours by taking into account the influence region of each canopy. We also present two efficient strategies to filter out erroneously detected canopy regions without having any height thresholds. Experiments are carried out on eight test DSMs composed of different types of citrus orchards with varying densities and canopy sizes. Extensive comparisons to the state-of-the-art approaches reveal that our proposed approach provides superior detection and delineation performances through supporting a nice balance between precision and recall measures.     

Novel fusion approach on automatic object extraction from spatial data: case study Worldview-2 and TOPO5000

The automatic extraction of information content from remotely sensed data is always challenging. We suggest a novel fusion approach to improve the extraction of this information from mono-satellite images. A Worldview-2 (WV-2) pan-sharpened image and a 1/5000-scaled topographic vector map (TOPO5000) were used as the sample data. Firstly, the buildings and roads were manually extracted from WV-2 to point out the maximum extractable information content. Subsequently, object-based automatic extractions were performed. After achieving two-dimensional results, a normalized digital surface model (nDSM) was generated from the underlying digital aerial photos of TOPO5000, and the automatic extraction was repeated by fusion with the nDSM to include individual object heights as an additional band for classification. The contribution was tested by precision, completeness and overall quality. Novel fusion technique increased the success of automatic extraction by 7% for the number of buildings and by 23% for the length of roads.