共查询到10条相似文献，搜索用时 125 毫秒
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选择山西太谷一个 5km× 5km的实验区 ,利用样条采样框架结合GVG农情采样系统调查农作物分类成数。同时借助QuickBird甚高分辨率遥感影像进行地面作物种植地块勾绘 ,并派出地面调查队伍进行作物填图 ,统计汇总出的农作物分类成数的真实值。然后将两种不同方法得出的分类成数进行对比 ,发现利用样条采样框架和GVG农情采样系统对于大宗粮食作物分类成数的调查相对误差在 3%以内 ,能够满足中国农情遥感速报系统的运行需要。而对于小成数作物的调查精度较低 ,且存在漏采现象 ,不能满足需求 ,同时也由于漏采现象的存在和图片判读的主观性。利用样条采样框架和GVG农情采样系统获取的大宗作物分类成数略大于真实值 ,存在少量的系统误差 ,需要进行地面验证并加以克服。 相似文献
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测量标志管理是一项系统性、持续性的工作,当前的管理系统往往缺乏对测量标志整个生命周期的跟踪反馈,难以形成有效的监管,技术手段急需改善和提升。本文立足当前测绘信息化发展的现状,对测量标志动态管理需求进行了全面的分析,从系统的逻辑架构、网络架构、数据组织、平台结构及安全性控制等方面阐述了测量标志动态管理信息系统的设计与实现,并结合数字城市、天地图·广东、广东省国土资源在线巡查系统,以及实际业务需求,开发完成了一个具有合理负载且维护方便的广东省测量标志管理信息系统。结果表明,该系统改变了测量标志传统管理模式,满足标志点巡查、更新、动态管理的需要,提高了测量标志的监管水平,对维护测量标志生命周期的各个环节都具有现实和科学意义。 相似文献
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This paper describes work undertaken to measure deformation of a pavement within the Newcastle University Rolling Load Facility (NUROLF). Precise three dimensional measurements of the pavement have been produced from stereo-imagery taken with diVerent cameras, using both analytical and digital photogrammetric instrumentation. The photogrammetric measurements, and those from the existing system consisting of an array of linear voltage displacement transducers, have been compared with measurements produced using a digital level. Encouraging results have been achieved and photogrammetry has been shown to be capable of producing a similar accuracy to the existing system. There are many advantages associated with a photogrammetric survey but attempts to establish a permanent, automated photogrammetric system for the rolling load facility at a reasonable cost have so far been unsuccessful. It is anticipated that, with the falling cost of high resolution digital sensors, such a system will soon be possible. 相似文献
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根据水下河床水深点测量采样的既有规则格网法又有三角形法二者优点的四边形法绘制河床等深线图,该法数据结构简单,编程方便,速度快。文 图表对水下对河床水深点的数据数据结构,四边形的构万能主等深线的追踪作了详细的讨论。 相似文献
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Mobile in‐situ sensor platforms such as Unmanned Aerial Vehicles can be used in environmental monitoring. In time‐critical monitoring scenarios as for example in emergency response, and in the exploration of highly dynamic phenomena, obtaining the relevant data with one or few mobile sensors is challenging. It requires an intelligent sampling strategy that integrates prior information and adapts to the dynamics of the observed phenomenon, based on the collected sensor data. Available information about the observed phenomenon may be incomplete or imprecise and therefore insufficient for quantitative modeling. We address this problem by reasoning about the plume movement and size on a qualitative level and present an algorithm for tracking a dynamic plume that integrates this qualitative information with the collected sensor data. We evaluate our algorithm using simulated data sets of three different moving and expanding gas plumes. By means of simulations we show that the qualitative methods can be used to infer new information about the properties of a moving plume and to adapt the sensor movement for tracking the plume. Both can be done with low computational effort, without absolute positioning capability of the sensor, and with less input information than required by quantitative approaches. 相似文献
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人口抽样调查是通过人口样本估算区域人口总体的一种手段。由于人口分布通常具有空间差异性,传统的抽样调查理论难以满足日益增长的空间抽样需求,合理高效的人口空间抽样调查方法对于人口统计、研究人类活动、解决城市问题等有重要意义。本文提出一种基于多源信息与深度学习特征提取的人口空间抽样方法。在不透水面信息的辅助下,利用四叉树分割进行分层抽样,初步选择出可能存在人口分布的调查样本,并通过深度学习的常用模型——卷积神经网络估算样本建筑物密度,以辅助最终调查样本的选择与调查方案的制定。研究结果证明,该方法能够有效地筛选与人口分布密切相关的抽样区域,排除大量的无用样本,提高了人口调查的效率,节约了大量调查成本。 相似文献
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利用6个IGS跟踪站一周的静态数据,采用采样间隔为30 s的卫星钟差产品,对精密单点定位（PPP）整周模糊度的固定模式——PPP_AR模式和常规的浮点解模式下的定位精度和收敛时间进行了比较试验。结果表明,PPP_AR模糊度固定模式下,数据之间具有自洽性,定位精度在E-W和N-S两个方向的RMS都优于1 cm,在U-D方向优于3.5 cm,明显高于浮点解模式下的定位精度。且PPP_AR模式下整周模糊度的固定率都在93％以上。PPP_AR模式下的收敛时间集中在20～25 min,浮点解模式25～35 min。 相似文献
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Path segmentation methods have been developed to distinguish stops and moves along movement trajectories. However, most studies do not focus on handling irregular sampling frequency of the movement data. This article proposes a four‐step method to handle various time intervals between two consecutive records, including parameter setting, space‐time interpolation, density‐based spatial clustering, and integrating the geographic context. The article uses GPS tracking data provided by HOURCAR, a non‐profit car‐sharing service in Minnesota, as a case study to demonstrate our method and present the results. We also implement the DB‐SMoT algorithm as a comparison. The results show that our four‐step method can handle various time intervals between consecutive records, group consecutive stops close to each other, and distinguish different types of stops and their inferred activities. These results can provide novel insights into car‐sharing behaviors such as trip purposes and activity scheduling. 相似文献