基于J2EE的分布式WebGIS研究

在对比分析传统的WebGIS各种实现模式优缺点的基础上，探讨了利用企业级J2EE技术实现分布式WebGIS的解决方案，使WebGIS更好地满足企业级应用的需要。     

SAN技术在基础地理信息数据库系统建设中的应用

分析了基础地理信息数据库建设中对存储备份系统的需求和当前存储系统的组成及特点 ,提出了存储局域网在基础地理信息数据库系统建设中的应用方案 ,并介绍了其在陕西省基础地理信息数据库系统建设中的实现情况     

基于OpenGIS规范的地理信息系统组件的内核及功能设计

提出了符合OpenGIS规范的二维地理信息系统组件软件MapManager的设计思想,介绍了MapManager的设计过程,并对其不足和进一步研究方向进行了讨论。     

面向数字化测绘生产工作流的Web存储系统

讨论了一个面向工作流的项目管理系统中,各类计划、实施、监督管理、汇总报表等结构化文档及非结构化文档的存储访问系统的构造方法,并设计与实现了一个数字化测绘生产管理系统实例。     

基于二维直接线性变换的数字相机畸变模型的建立

提出并论证了基于二维直接线性变换的畸变的校正方法。本方法特别适用于各类固态摄像机(CCD、CID、PSD)的畸变模型的建立,以补偿各类像点系统误差。     

Assessing the utility WorldView-2 imagery for tree species mapping in South African subtropical humid forest and the conservation implications: Dukuduku forest patch as case study

Indigenous forest biome in South Africa is highly fragmented into patches of various sizes (most patches < 1 km²). The utilization of timber and non-timber resources by poor rural communities living around protected forest patches produce subtle changes in the forest canopy which can be hardly detected on a timely manner using traditional field surveys. The aims of this study were to assess: (i) the utility of very high resolution (VHR) remote sensing imagery (WorldView-2, 0.5–2 m spatial resolution) for mapping tree species and canopy gaps in one of the protected subtropical coastal forests in South Africa (the Dukuduku forest patch (ca.3200 ha) located in the province of KwaZulu-Natal) and (ii) the implications of the map products to forest conservation. Three dominant canopy tree species namely, Albizia adianthifolia, Strychnos spp. and Acacia spp., and canopy gap types including bushes (grass/shrubby), bare soil and burnt patches were accurately mapped (overall accuracy = 89.3 ± 2.1%) using WorldView-2 image and support vector machine classifier. The maps revealed subtle forest disturbances such as bush encroachment and edge effects resulting from forest fragmentation by roads and a power-line. In two stakeholders’ workshops organised to assess the implications of the map products to conservation, participants generally agreed amongst others implications that the VHR maps provide valuable information that could be used for implementing and monitoring the effects of rehabilitation measures. The use of VHR imagery is recommended for timely inventorying and monitoring of the small and fragile patches of subtropical forests in Southern Africa.     

Use of WorldView-2 time series to establish a wetland monitoring program for potential offsite impacts of mine site rehabilitation

The Ramsar-listed wetlands of the Magela Creek floodplain, situated in the World Heritage Kakadu National Park, in northern Australia are recognised for their biodiversity and cultural values. The floodplain is also a downstream receiving environment for Ranger uranium mine, which is entering closure and rehabilitation phases. Vegetation on the floodplain is spatially and temporally variable which is related to the hydrology of the region, primarily the extent and level of inundation and available soil moisture. Time-series mapping of the floodplain vegetation will provide a contemporary baseline of annual vegetation dynamics to assist with determining whether change is natural or a result of the potential impacts of mine closure activities such as increased suspended sediment moving downstream. The research described here used geographic object-based image analysis (GEOBIA) to classify the upper Magela Creek floodplain vegetation from WorldView-2 imagery captured over four years (2010–2013) and ancillary data including a canopy height model. A step-wise rule set was used to implement a decision tree classification. The resulting maps showed the 12 major vegetation communities that exist on the Magela Creek floodplain and their distribution for May 2010, May 2011, June 2012 and June 2013 with overall accuracies of over 80% for each map. Most of the error appears to be associated with confusion between vegetation classes that are spectrally similar such as the classes dominated by grasses. Object-based change detection was then applied to the maps to analyse change between dates. Results indicate that change between dates was detected for large areas of the floodplain. Most of the change is associated with the amount of surface water present, indicating that although imagery was captured at the same time of year, the imagery represents different stages of the seasonal cycle of the floodplain.     

协同多源遥感数据的北亚热带森林蓄积量贝叶斯分层估测

精确估算森林蓄积量是国家实现2060年前碳中和目标的迫切需求,而基于遥感的森林蓄积量定量反演是当前遥感应用领域面临的重要挑战和研究热点.光学遥感数据由于无法获取森林高度信息并存在信号饱和问题,反演森林蓄积量的精度较低,而机载Lidar数据能获取高度信息,但成本高、观测范围有限.本研究利用Sentinel-2多光谱、资源...     

基于Sentinel-2A/B的新疆典型城市不透水面提取及空间差异分析

随着城市化进程加快,自然地表物理结构及属性的变化使得城市不透水面不断增加,进而造成城市土地覆盖类型剧烈变化,极大地影响着其环境质量和生态循环。因此,探讨不透水面的空间变化规律,对建设生态、和谐、宜居城市变得极为重要。本文选取新疆维吾尔自治区（简称新疆）典型城市（乌鲁木齐、喀什、哈密及克拉玛依）主城区为研究区,通过对Sentinel-2A/B影像L2范数归一化处理,结合增强型归一化差值不透水面指数ENDISI（Enhanced Normalized Difference Impervious Surface Index）,采用最大类间方差法（OTSU）自适应确定阈值,提取2017年和2019年新疆典型城市不透水面。结果表明：L2范数归一化处理与ENDISI结合能较好的突显不透水面与非不透水面的差异;OTSU自适应确定的阈值能够很好的区分不透水面,经示例验证（2019年乌鲁木齐主城区）,不透水面提取结果总体精度为86.60%,Kappa系数为0.73。通过对不透水面空间差异分析可知：从剖面线角度分析得出乌鲁木齐北部、喀什中部和北部及哈密中东部和北部ENDISI指数值均显著增加,而克拉玛依北部和中西部区域ENDISI指数值增加较少;从不透水面盒维数分析中得出,新疆典型城市的盒维数值均呈增加趋势,城市结构复杂度不断增强,其中哈密盒维数值最大,乌鲁木齐盒维数值最低,且哈密的盒维数值变化幅度最大,克拉玛依的盒维数值变化最小。本文可为新疆典型城市内涵式发展提供科学指导,为干旱区城市生态环境保护提供理论依据。