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Observations of living organisms by citizen scientists that are reported to online portals are a valuable source of information. They are also a special kind of volunteered geographic information (VGI). VGI data have issues of completeness, which arise from biases caused by the opportunistic nature of the data collection process. We examined the completeness of bird species represented in citizen science observation data from eBird and iNaturalist in US National Parks (NPs). We used approaches for completeness estimation which were developed for data from OpenStreetMap, a crowdsourced map of the world. First, we used an extrinsic approach, comparing species lists from citizen science data with National Park Service lists. Second, we examined two intrinsic approaches using total observation numbers in NPs and the development of the number of new species being added to the data-set over time. Results from the extrinsic approach provided appropriate completeness estimations to evaluate the intrinsic approaches. We found that total observation numbers are a good estimator of species completeness of citizen science data from US NPs. There is also a close relationship between species completeness and the ratio of new species added to observation data vs. observation numbers in a given year. 相似文献
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Validity of historical volunteered geographic information: Evaluating citizen data for mapping historical geographic phenomena 总被引:2,自引:0,他引:2
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Guiming Zhang A‐Xing Zhu Zhi‐Pang Huang Guopeng Ren Cheng‐Zhi Qin Wen Xiao 《Transactions in GIS》2018,22(1):149-164
Studies on volunteered geographic information (VGI) have focused on examining its validity to reveal geographic phenomena in relatively recent periods. Empirical evaluation of the validity of VGI to reveal geographic phenomena in historical periods (e.g., decades ago) is lacking, although such evaluation is desirable for assessing the possibility of broadening the temporal scope of VGI applications. This article presents an evaluation of the validity of VGI to reveal historical geographic phenomena through a citizen data‐based habitat suitability mapping case study. Citizen data (i.e., sightings) of the black‐and‐white snub‐nosed monkey (Rhinopithecus bieti) were elicited from local residents through three‐dimensional (3D) geovisualization interviews in Yunnan, China. The validity of the elicited sightings to reveal the historical R. bieti distribution was evaluated through habitat suitability mapping using the citizen data in historical periods. The results of controlled experiments demonstrated that suitability maps predicted using the historical citizen data had a consistent spatial pattern (correlation above 0.60) that reflects the R. bieti distribution (Boyce index around 0.90) in areas free of significant environmental change across historical periods. This in turn suggests that citizen data have validity for mapping historical geographic phenomena. It provides supporting empirical evidence for potentially broadening the temporal scope of VGI applications. 相似文献
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ABSTRACTVolunteer geographic information (VGI) and citizen science (CS) have been used as a way to promote a form of democratization of knowledge. Crowdsourcing facilitates the massive collection of data through nonexpert volunteers. This study compares 57 VGI and CS projects through a cross-case comparison method to explore the level of involvement of participants, based on three main analytic dimensions (project rationale, actor interaction, and data flow) and 12 sub-variables. The primary goal of this research is to analyze the purpose and the role of technology in VGI and CS projects, using three matrices to explore emerging trade-offs. Finally, we synthesized the workflow of VGI and CS project and compared based on project purposes. At the end of this study, five main purposes were found among the selected projects, uncovering that data collection is the most common purpose. A general workflow can be conceptualized, but detail implementation will involve various trade-offs, especially between local involvement and large-area expert-oriented protocol implementations. By exploring diverse relationships among selected variables of analysis in VGI and CS projects, this study pretends to build a foundation for larger, global meta-analysis that can bring some transparency in the epistemic interactions between experts and nonexperts. 相似文献
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《ISPRS Journal of Photogrammetry and Remote Sensing》2000,55(3):201-213
In this paper, we present a quality evaluation of two-dimensional building acquisition. We propose methods for identification and quantification of differences between independently acquired regions, and we present a systematic classification of those differences. Differences between acquired sets Rj={ri}j of region rij depend on the context of observation, on the technique of observation, etc. We distinguish topological and geometrical differences. Topological differences refer to the interior structure of a set of regions as well as to the structure of the boundary of a single region. Geometrical differences refer to the location of the boundary of a single region or of a set of regions, independent of their representation and of the structure of the boundaries.Identification of differences requires a matching of two data sets R1 and R2, which is done here by weighted topological relationships. For the identification of topological differences between two sets R1 and R2 of regions, we use the two region adjacency graphs (RAGs). For an identification of geometrical differences, we use the zone skeleton between two matched subsets rp1 and rq2 of the given sets. The zone skeleton is labeled with the local distances of the corresponding boundaries of the subsets; especially, we investigate its density function. An example based on two real data sets of acquired ground plans of buildings, shows the feasibility of the approach. 相似文献
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随着空间地理信息以及各种新型地图产品在各个领域的广泛应用,人们发现不同时期,应用需求对空间地理信息组织表达的要求是不同的,不同领域和部门对地理信息的组织表达方式也是不同的。但是,目前空间地理信息的共享和互操作、空间地理信息的多尺度分析与表达等,都要求空间地理信息的组织与表达要科学、合理和规范,否则难以满足测绘信息服务化及信息化测绘体系的建设。本文以交通类信息组织表达为例,详尽阐述当前空间地理信息组织表达的现状,分析其原因,并提出了解决这一问题的思路和方法,为今后信息化测绘体系建设、数据库数据组织和地理信息表达,提供理论和方法借鉴。 相似文献
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鄱阳湖地区是中国九大商品粮生产基地之一,同时这个区域也是洪水经常泛滥的地方。为了减少洪水对人们生命财产造成的危害,我们在江西省科技厅、江西省水利厅等单位的大力支持下,开发了鄱阳湖区防汛抗洪地理信息系统。该系统融合了多种空间数据的采集、传输和处理技术。多种技术生产了多源数据,为快速准确地决策提供了丰富详实的信息支持,但同时也对空间数据的质量控制提出了较高的要求。本文按照空间数据质量问题产生的先后顺序,对鄱阳湖区防汛抗洪地理信息系统空间数据获取、存储、处理、传输、应用等五个阶段的误差进行了分类,并分析了产生的原因,提出了误差的改正方法,从而控制了鄱阳湖区防汛抗洪空间数据质量,并为鄱阳湖区防汛抗洪地理信息系统的建设提供了空间数据。 相似文献
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地理信息服务中数据传输性能分析 总被引:2,自引:0,他引:2
地理信息服务系统具有数据密集型和计算密集型的特点,对网络环境的设置有着特殊的需求。本文从地理信息服务系统中对数据传输应用的角度出发,从网络数据传输协议的传输层和应用层两个层次分析地理信息服务系统应用的特殊性,并根据系统应用的特殊需求提出相应的解决方案,提高整个应用系统中各类数据传输的效率、性能和系统运行的稳定性,提高地理信息服务系统为多用户提供地图服务、位置服务以及各种应用服务的综合能力。提高系统适应多用户并发访问海量数据的地图服务作业和频繁访问实效性很强的位置服务作业的能力。 相似文献
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提出了空间基础地理信息不对称的基本含义,并在信息化建设过程中的表现,分析了产生的原因及其解决办法。从某种意义上说,空间地理信息数据的生产,交换中的不对称本质上就必然导致利益上的不对称。 相似文献
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The key to develop 3-D GISs is the study on 3-D data model and data structure. Some of the data models and data structures have been presented by scholars. Because of the complexity of 3-D spatial phenomenon, there are no perfect data structures that can describe all spatial entities. Every data structure has its own advantages and disadvantages. It is difficult to design a single data structure to meet different needs. The important subject in the 3-D data models is developing a data model that has integrated vector and raster data structures. A special 3-D spatial data model based on distributing features of spatial entities should be designed. We took the geological exploration engineering as the research background and designed an integrated data model whose data structures integrats vector and raster data by adopting object-oriented technique. Research achievements are presented in this paper. 相似文献
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CHENG Penggen GONG Jianya WANG Yandong SUI Haigang CHENG Penggen Doctoral Candidate Associate Professor National Laboratory for Information Engineering in Surveying Mapping Remote Sensing WTUSM Luoyu Road Wuhan China 《地球空间信息科学学报》1999,2(1):78-85
The key to develop 3-D GISs is the study on 3-D data model and data structure. Some of the data models and data structures have been presented by scholars. Because of the complexity of 3-D spatial phenomenon, there are no perfect data structures that can describe all spatial entities. Every data structure has its own advantages and disadvantages. It is difficult to design a single data structure to meet different needs. The important subject in the3-D data models is developing a data model that has integrated vector and raster data structures. A special 3-D spatial data model based on distributing features of spatial entities should be designed. We took the geological exploration engineering as the research background and designed an integrated data model whose data structures integrats vector and raster data byadopting object-oriented technique. Research achievements are presented in this paper. 相似文献
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西部基础空间数据质量检查与评价技术研究 总被引:1,自引:0,他引:1
针对西部测图工程,采用基于地理实体的质量检查方法,并利用云模型和粗集理论进行地图质量评价。首先分析西部测区特征,在此基础上建立数字线划图质量模型,进而总结质量元素及其相应的质量子元素。其次,归纳总结基本空间算子,形成具体检查规则。然后,根据粗集的属性依赖度计算各个质量元素和质量子元素的权重,接着对评语进行云模型化,根据X-条件云发生器和最大隶属原则判断地图等级。最后研制开发了质量检查、评价软件。实验证明,检查、评价方法可行,软件自动化程度高,并具有良好的交互性。 相似文献