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康宏伟 《测绘与空间地理信息》2011,34(4):174-176
结合轧机基础施工和设备安装实例,总结了设备基础施工放样和安装测量中具有普遍性的技术工作,针对特殊预埋件的放样定位采用独立建网一次固定的方法,设备安装采用专用控制网,通过角度严密归方、精密校正距离的方法,用高精度测量仪器直接控制安装施工,保证了基础预埋件位置的准确和设备各机组之间严密的位置关系。 相似文献
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近几年来,随着自动化及人工智能的普及,许多工厂作业线上的工作人员已被机器取代,而这些设备的安装,对点位精度要求非常高。本文通过精密放样测量在设备安装中的应用实例,对精密放样测量的方法及精度的控制进行了探讨,总结出了一些运用中的经验。 相似文献
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利用原基础的大型设备安装测设问题探讨 总被引：2，自引：0，他引：2
工程测量中有时会遇到设备的重装和利用原基础安装新设备的问题 ,本文结合实例就在原基础上进行设备安装时的测设问题作了有益探讨。 相似文献
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反应堆内设备的安装测量是核电建设中的关键性工作,其测量环境突出,观测条件差,而且观测精度要求高,安装定位精度要求达到0.1 mm,甚至更高.主要探讨反应堆内压力容器、装卸料机、主泵和蒸发器等主要设备的安装测量方法. 相似文献
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本文主要对大型设备的安装测量工作方法和步骤以及精度要求进行了分析总结。提出的一些建议，对于开展工程测量工作具有一定的实际意义。 相似文献
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1999-2020年长江经济带(江苏段)生态环境变化监测及人类活动驱动分析 总被引：1，自引：0，他引：1
协调区域城镇化与生态环境保护之间的关系,是推动我国长江经济带可持续发展的核心问题之一。针对现有研究中,生态环境变化与人类活动驱动之间的响应关系缺少时空对应的数据支持、影响过程不明的问题,本文充分利用多源卫星遥感技术在处理和提取时空信息上的优势,以长江经济带江苏段沿江县区为例,利用1999-2000年、2009-2010年和2019-2020年3期Landsat系列遥感影像,通过RSEI模型定量分析研究区1999-2020年间区域生态环境时空变化规律,并引入人工不透水面（IS）及夜景灯光（NTL）等时空信息指标,定义各县区IS面积占比和IS区域NTL辐亮度均值,用于定量探究不同区域、不同强度下人类活动（城镇化）对生态环境的影响。研究结果表明：①1999-2020年间,江苏省沿江各区县城镇化区域及其周边区域生态环境质量下降趋势明显。其中,2000-2009年间,研究区各县区IS区域面积快速增加,导致其区域生态环境质量明显下降。而2010-2020年间,部分城镇化区域绿化面积增加,促使其区域生态环境质量缓慢提升。②研究区各县区IS面积占比与其RSEI均值呈现明显函数负相关性,而IS区域NTL辐亮度均值与其RSEI均值的函数负相关性相对减弱,尤其是IS面积占比超0.3的县区,城镇化与生态环境交互耦合关系复杂性增强,其详细函数模型需进一步研究。 相似文献
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北斗卫星导航系统(BDS)于2020年建成并开始向全球提供服务。如何提高其在防灾减灾领域的应用是目前关注的焦点。本文梳理了国内外采用BDS数据开展地壳形变(包括同震和震间形变获取)研究的现状,总结了BDS数据的定位精度,归纳出基于BDS数据的地壳形变监测需要进一步解决、有待拓展的关键问题:①扩展GNSS地壳形变监测的内涵,采用GPS与BDS双模或多模算法提高形变解算精度;②开展BDS实时形变监测在地质灾害早期识别中的应用;③开发、发布相关数据处理算法与软件系统,切实推进BDS在高精度地壳形变监测领域的应用。 相似文献
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对GIS中常见的数据转换进行了细致的研究 ,为数据转换中的质量保证提供了一种理论上严谨的检验手段 ,首次提出了用代数同构的思想来检测网络环境下数据共享的可信度 相似文献
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《制图学和地理信息科学》2013,40(4):175-186
Understanding the spatial dimension of fear of crime in the urban environment is important to understanding behaviors in response to this concern. Making this connection between perception and action has long been a goal of scholars in the social and health sciences, though this complex relationship has yet to be fully elucidated. Specifically, in studies on fear of crime and its influence on behavior, a variety of definitions and methods have been employed. This situation has yielded insights, as well as inconsistencies. In the past decade, Geographic Information Systems (GIS) has been added to this methodological mix, though it too has contributed limited understanding of the environmental perception-behavior nexus. During this time, some scholars have integrated a traditional technique for accessing environmental perception, the sketch map, with this newer technology. This article provides a review and critical assessment of the way GIS has been used to understand fear of crime, specifically through the integration of sketch maps. This focus is framed by an overview of substantive and methodological concerns and concludes with a discussion of continued research needs. As behavioral responses to fear of crime are acknowledged to impact physical and mental health and overall well-being, in addition to the viability of neighborhoods, research in this area will continue apace. However, for integration of sketch maps in GIS to be a valuable methodological contributor to this line of inquiry, users of the approach must understand its complexities. This article outlines these issues so that they may be considered in future research and may improve the ability for this approach to yield new understanding of fear of crime. 相似文献
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Pastoralism is a major occupation in Africa’s Sahel region, which spans from Senegal in the west to Ethiopia in the east and has a semi-arid climate. Pastoralists from the region are usually nomadic, moving regularly in search of water and pasture, often for hundreds of kilometers. Traditionally, pastoralists have relied on historical knowledge and transhumance pathways to reach the water bodies (WB). Due to climatic conditions, a vast majority of the WBs in this region are small, sporadic, and ephemeral, therefore there is a need to map and frequently monitor water availability. Remote sensing observations can be used to complement current monitoring efforts. High-resolution near-daily imagery from the recently launched PlanetScope (PS) constellation of small satellites has the potential to complement the existing medium-resolution and infrequent but well established and extensively calibrated sensors like Landsat. The aim of this study is to investigate the performance and applicability of high-resolution PS data to detect and monitor WBs in the Ferlo region of West Africa, in comparison to Landsat-8 imagery. The results indicate that for cloud-free days, PS data was comparable (r >0.88; ubRMSE <0.01) to Landsat, but due to inadequate cloud masking, the results were poor for cloudy days (r < 0.49 and ubRMSE>0.058). The PS images were able to detect nearly 95% of the WBs, whereas Landsat was able to identify only 32% at the water fraction threshold >40%. Initial results from this study show that the high spatial and temporal resolution PS datasets show promise in monitoring WBs in arid regions of West Africa. 相似文献
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A geometric-based approach for road matching on multi-scale datasets using a genetic algorithm 总被引：1，自引：0，他引：1
Alireza Chehreghan 《制图学和地理信息科学》2018,45(3):255-269
Object matching is used in various applications including conflation, data quality assessment, updating, and multi-scale analysis. The objective of matching is to identify objects referring to the same entity. This article aims to present an optimization-based linear object-matching approach in multi-scale, multi-source datasets. By taking into account geometric criteria, the proposed approach uses real coded genetic algorithm (RCGA) and sensitivity analysis to identify corresponding objects. Moreover, in this approach, any initial dependency on empirical parameters such as buffer distance, threshold of spatial similarity degree, and weights of criteria is eliminated and, instead, the optimal values for these parameters are calculated for each dataset. Volunteered geographical information (VGI) and authoritative data with different scales and sources were used to assess the efficiency of the proposed approach. According to the results, in addition to an efficient performance in various datasets, the proposed approach was able to appropriately identify the corresponding objects in these datasets by achieving higher F-Score. 相似文献
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Urban sprawl has led to environmental problems and large losses of arable land in China. In this study, we monitor and model urban sprawl by means of a combination of remote sensing, geographical information system and spatial statistics. We use time-series data to explore the potential socio-economic driving forces behind urban sprawl, and spatial models in different scenarios to explore the spatio-temporal interactions. The methodology is applied to the city of Wuhan, China, for the period from 1990 to 2013. The results reveal that the built-up land has expanded and has dispersed in urban clusters. Population growth, and economic and transportation development are still the main causes of urban sprawl; however, when they have developed to certain levels, the area affected by construction in urban areas (Jian Cheng Qu (JCQ)) and the area of cultivated land (ACL) tend to be stable. Spatial regression models are shown to be superior to the traditional models. The interaction among districts with the same administrative status is stronger than if one of those neighbors is in the city center and the other in the suburban area. The expansion of urban built-up land is driven by the socio-economic development at the same period, and greatly influenced by its spatio-temporal neighbors. We conclude that the integration of remote sensing, a geographical information system, and spatial statistics offers an excellent opportunity to explore the spatio-temporal variation and interactions among the districts in the sprawling metropolitan areas. Relevant regulations to control the urban sprawl process are suggested accordingly. 相似文献
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Agricultural activities mainly occur in rural areas; recently, ecological conservation and biological diversity are being emphasized in rural communities to promote sustainable development for rural communities, especially for rural communities in Taiwan. Therefore, since 2005, many rural communities in Taiwan have compiled their own development strategies in order to create their own unique characteristics to attract people to visit and stay in rural communities. By implementing these strategies, young people can stay in their own rural communities and the rural communities are rejuvenated. However, some rural communities introduce artificial construction into the community such that the ecological and biological environments are significantly degraded. The strategies need to be efficiently monitored because up to 67 rural communities have proposed rejuvenation projects. In 2015, up to 440 rural communities were estimated to be involved in rural community rejuvenations. How to monitor the changes occurring in those rural communities participating in rural community rejuvenation such that ecological conservation and ecological diversity can be satisfied is an important issue in rural community management. Remote sensing provides an efficient and rapid method to achieve this issue. Segmentation plays a fundamental role in human perception. In this respect, segmentation can be used as the process of transforming the collection of pixels of an image into a group of regions or objects with meaning. This paper proposed an algorithm based on the multiphase approach to segment the normalized difference vegetation index, NDVI, of the rural communities into several sub-regions, and to have the NDVI distribution in each sub-region be homogeneous. Those regions whose values of NDVI are close will be merged into the same class. In doing so, a complex NDVI map can be simplified into two groups: the high and low values of NDVI. The class with low NDVI values corresponds to those regions containing roads, buildings, and other manmade construction works and the class with high values of NDVI indicates that those regions contain vegetation in good health. In order to verify the processed results, the regional boundaries were extracted and laid down on the given images to check whether the extracted boundaries were laid down on buildings, roads, or other artificial constructions. In addition to the proposed approach, another approach called statistical region merging was employed by grouping sets of pixels with homogeneous properties such that those sets are iteratively grown by combining smaller regions or pixels. In doing so, the segmented NDVI map can be generated. By comparing the areas of the merged classes in different years, the changes occurring in the rural communities of Taiwan can be detected. The satellite imagery of FORMOSA-2 with 2-m ground resolution is employed to evaluate the performance of the proposed approach. The satellite imagery of two rural communities (Jhumen and Taomi communities) is chosen to evaluate environmental changes between 2005 and 2010. The change maps of 2005–2010 show that a high density of green on a patch of land is increased by 19.62 ha in Jhumen community and conversely a similar patch of land is significantly decreased by 236.59 ha in Taomi community. Furthermore, the change maps created by another image segmentation method called statistical region merging generate similar processed results to multiphase segmentation. 相似文献
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第三次全国国土调查已于2019年全面开展,图斑地类认定是该项工作的重点和难点。本文根据笔者所在单位在华南地区多个项目的实施经验,针对动土、建设用地和闲置用地3类重点图斑中常见的容易判断错误的问题,通过影像图、现场照片对比及国家发布的认定依据进行分析,总结了一套地类认定的规律和经验,有助于三调工作中快速、准确地认定地类,避免了返工和数据库的反复修改,从而可提高作业队伍在三调工作中的工作效率和工作质量。 相似文献