美国空军卫星控制网的现状与发展趋势

近几年的几场局部战争部分表明了现代军事航天系统的重要性。本文主要介绍了美国最重要的一个军事航天测控网－－空军卫星控制网的情况，希望能对了解美国军事航天测控体制有所帮助。     

语音指导查询与数据自动传输方法

我国电子商务刚刚起步,应根据我国电子商务发展的现状,结合发达国家的先进经验,对相应的网上交易涉税问题尽早给予解决。电子商务的商品交易方式、支付方式等都与传统的方式有着很大的不同,这就给税收制度带来了挑战。本文将对电子商务所涉及的税收问题作一论述。     

利用卫星遥感技术辅助城乡规划督察成果应用研究——以2008～2011年郑州市动态监测成果为例

遥感影像具有重复成像的特点,利用卫星遥感技术能动态地反映城市建设用地变化的过程信息,因此卫星遥感技术辅助城乡规划督察成为有效应用遥感技术的主要方法之一。本文采用郑州市2008～2011年连续四年度的利用卫星遥感技术辅助城乡规划动态监测成果进行归纳,分析反映城乡建设行为的变化图斑的规律和特点,通过地理信息系统及相关统计手段研究2008～2011年四年间郑州市城市建设用地的特点及趋势,对遥感监测成果的进一步应用做可行性探讨。     

城市三维形态与热环境的相关关系研究——以大连市金普新区为例

由城市各种实体空间结构所构成的三维形态是城市形态的重要组成部分。而城市的空间结构与城市空间环境的热场分布也有着密不可分的关系。本文运用地理信息系统与遥感技术,获取三维形态指标与地表温度,对各因子进行回归分析,建立城市空间形态热场分布研究的回归模型。分析了金普新区空间实体的占空度、错落度、建筑密度等空间形态对城市亮度温度的影响,发现占空度与城市亮温成正相关并且相关性较高,绿化率与亮温成负相关,而建筑密度与错落度对城市热场的影响较小。     

1999年至2010年呼伦贝尔市重要湿地遥感动态变化研究

以1999年、2002年和2010年3期TM/ETM影像为数据源,综合应用RS与GIS技术,以呼伦贝尔市西南六县为重点研究区,对其湿地进行专题信息提取和分类,了解呼伦贝尔湿地近10多年来的动态变化。结果表明：近11年来,研究区湿地面积萎缩严重,总面积减少3 522.07 km2,变化率为36.5%。其中新巴尔虎右旗和陈巴尔虎旗湿地面积减少最多,变化主要包括湿地向非湿地的转变和草甸沼泽湿地向草本沼泽湿地的转变。初步反映了呼伦贝尔盟湿地的退化现状,为进一步加强湿地保护与生态恢复提供了依据。     

Quantifying and understanding land cover changes by large and small oil palm expansion regimes in the Peruvian Amazon

With rapid increases in global food demand and production, oil palm expansion constitutes a major emerging challenge for forest conservation in Amazonia and other tropical forest regions. This threat is evident in the Peruvian Amazon, where local and national incentives for oil palm cultivation along with growing large-scale investments translate into accelerated oil palm expansion. Environmental sustainability of oil palm cultivation in the Peruvian Amazon is contingent on policy incentives for expansion onto already-cleared lands instead of biodiverse, high carbon primary rainforests. Previous research indicates that while industrial plantations use less land area than local smallholders, companies have a higher tendency to expand into primary rainforests. However, the motivations behind these differing expansion scenarios remain unclear. In this study we combine data from optical and radar satellite sensors with training information, field discussions, and review of public documents to examine the policy incentives and spatial patterns associated with oil palm expansion by smallholders and industries in one of Peru’s most rapidly changing Amazonian landscapes: the Ucayali region of the city of Pucallpa. Based on our satellite-based land cover change analysis, we found that between 2010 and 2016, smallholders utilized 21,070 ha more land area for oil palm than industries but industrial expansion occurred predominantly in old growth forests (70%) in contrast to degraded lands for smallholders (56%). Our analysis of national policies related to oil palm expansion reveal policy loopholes associated with Peru’s “best land use” classification system that allow for standing forests to undergo large-scale agricultural development with little government oversight. We conclude that both sectors will need careful, real-time monitoring and government engagement to reduce old-growth forest loss and develop successful strategies for mitigating future environmental impacts of oil palm expansion.     

基于RS和GIS的土地利用结构动态变化及发展预测研究--以南通市为例

在遥感技术（RS）与地理信息系统（GIS）技术支持下,通过对南通市区2003年、2005年、2007年三期中巴地球资源卫星CBERS遥感影像数据进行处理,并通过对处理后的图像进行非监督分类获得了南通市三期土地利用类型图和不同土地利用类型的面积数据,之后通过对三期土地利用类型数据进行叠加分析,得到了南通市区土地利用类型转移矩阵,计算了各种地类的变化率,并对未来南通市区土地利用变化情况做出了预测,结果表明：1.南通市土地变化总体呈现出建设用地持续快速增长,耕地显著减少的趋势;2.导致这种变化的直接诱因则是南通城市化进程加快,经济发展迅速,建筑用地正在不断的取代耕地和其他用地;3.如果以当前的变化模式稳定延续下去,在2012年后很短时间内南通市区建设用地面积将占全区总面积的50%以上,同时耕地面积会进一步大幅下降,土地非农化的趋势将更加明显。     

Environmental Outcomes of Urban Land System Change: Comparing Riparian Design Approaches in the Phoenix Metropolitan Area

In the face of climate change and other environmental challenges, an increasing number of cities are turning to land design to enhance urban sustainability. Land system architecture (LSA)—which examines the role of size, shape, distribution, and connectivity of land units in relation to the system’s social-environmental dynamics—can be a useful perspective for examining how land contributes to the social and environmental aspects of urban sustainability. There are two gaps, however, that prevent LSA from fully contributing to urban sustainability dialogues. First, it is not well understood how urban design goals, as expressed by urban planners and other practitioners, relate to LSA and environmental outcomes. Second, most LSA work focuses on individual environmental outcomes, such as the urban heat island effect, instead of considering the broader suite of outcomes that LSA changes impact. Here, we undertake an integrated assessment of LSA impacts on surface urban heat island (based on land surface temperature), vegetation presence/health (based on NDVI), and bird biota at two riparian sites with different design intentions in the Phoenix, Arizona metropolitan area. The Rio Salado in Tempe underwent a city-led, infill redevelopment that mixed economic, recreational, and flood control design goals. The New River in Peoria experienced a more typical developer-driven urbanization. The contexts and design goals of the sites generated differences in their LSA, but only a few of these differences were sufficiently unique to contribute to divergent environmental outcomes. These differences reside in (1) the greater distribution of recreational land-covers and (2) increased surface water at the Rio Salado site compared to the New River site. Both changes are linked to land-cover patches becoming greener and cooler as well as a greater presence of waterbird and warbler species at the Rio Salado site. The distinctions between the sites provide insight for crafting design goals for redeveloping or restoring urban riparian landscapes in the Phoenix metropolitan area that are grounded in LSA. With the incorporation of additional relevant variables, especially socioeconomic ones, the research approach employed in this study provides a foundation for the assessment of other urban land system change.     

Remote sensing-based detection of agricultural land losses around Greater Cairo since the Egyptian revolution of 2011

Over the last four decades, the loss of agricultural land has been observed in Egypt at high rates. However, the highest rates of losses have occurred since the January 25th revolution in 2011. Greater Cairo (GC), which is the largest metropolitan in Egypt, has witnessed a massive loss of agricultural land since the 2011 revolution. However, until now, no study or official report has revealed the volume of agricultural land losses in this region. This study quantifies agricultural land losses around the GC using Landsat satellite images from 2010 and 2018. Supervised classification was performed using the maximum likelihood algorithm in QGIS software. A post-classification comparison method was applied to detect the land use/land cover changes between the classified images; then, the loss of agricultural land was quantified using Arc GIS software. Visualizations of the gains and losses in agricultural land and the spatial trends of agricultural land losses were created using TerrSet software. The results show that 9600 ha of agricultural land were converted to urban use during 2010–2018, which means that the annual rate of agricultural land loss has tripled and now reaches approximately 1200 ha per year. Decay of executive authority, rapid population growth, real estate market speculation and fragmentation of agricultural land were the main driving factors of agricultural land losses during this period. The results of this research may help decision makers understand the current high rate of agricultural land loss. Hence, appropriate strategies may be adopted to prevent future losses of this valuable land.     

基于遥感和GIS的长春市城乡建设用地发展演变

本文采用1968年、2002年和2010年不同历史阶段的遥感影像数据,借助于ArcGIS软件,对长春市建成区及其周边城乡建设用地规模与形态的发展演变过程、特征及其原因进行研究,结果表明:长春市城乡建设用地由快速的、蔓延式的无序扩张向城市规划引导下的适度、有序扩张转变,城市规划对建设用地布局的引导作用增强.道路交通尤其是...