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棉花学报 2002年第S1期14卷 47-47页

作者： Khairy M.SOLIMAN allan zipf Sukumar SAHA Department of Plant and Soil Science Alabama A&M UniversityNormalALDepartment of Plant and Soil ScienceAlabama A&M UniversityNormalALUSDA/ARS/CSRLMississippi StateUSA

The demand for high strength fiber in rawcotton has increased because of the widespreaduse of high speed spinning technology in theyarn and textile *** ofcotton fiber quality through

关键词： Cotton cotton spinning probes genetics yielding developmental differentially homologous remaining

Completeness of citizen science biodiversity data from a volunteered geographic information perspective

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Geo-Spatial Information Science 2017年第1期20卷 3-13页

作者： Clemens Jacobs Alexander zipf GIScience Research Group Institute of GeographyHeidelberg UniversityHeidelbergGermany

Observations of living organisms by citizen scientists that are reported to online portals are a valuable source of *** 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 *** 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 ***,we used an extrinsic approach,comparing species lists from citizen science data with National Park Service ***,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 *** from the extrinsic approach provided appropriate completeness estimations to evaluate the intrinsic *** found that total observation numbers are a good estimator of species completeness of citizen science data from US *** is also a close relationship between species completeness and the ratio of new species added to observation data *** numbers in a given year.

关键词： Citizen science Volunteered Geographic Information(VGI) data quality completeness

OpenStreetMap data quality enrichment through awareness raising and collective action tools——experiences from a European project

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Geo-Spatial Information Science 2018年第3期21卷 234-246页

作者： Amin Mobasheri Alexander zipf Louise Francis GIScience Research Group Institute of GeographyHeidelberg UniversityHeidelbergGermany Mapping for Change(Co.Ltd.) LondonUnited Kingdom

Nowadays,several research projects show interest in employing volunteered geographic information(VGI)to improve their systems through using up-to-date and detailed *** European project CAP4Access is one of the successful examples of such international-wide research projects that aims to improve the accessibility of people with restricted mobility using crowdsourced *** this project,OpenStreetMap(OSM)is used to extend OpenRouteService,a well-known routing ***,a basic challenge that this project tackled was the incompleteness of OSM data with regards to certain information that is required for wheelchair accessibility(*** information,kerb data,etc.).In this article,we present the results of initial assessment of sidewalk data in OSM at the beginning of the project as well as our approach in awareness raising and using tools for tagging accessibility data into OSM database for enriching the sidewalk data *** experiments have been carried out in different European cities,and discussion on the results of the experiments as well as the lessons learned are *** lessons learned provide recommendations that help in organizing better mapping party events in the *** conclude by reporting on how and to what extent the OSM sidewalk data completeness in these study areas have benefited from the mapping parties by the end of the project.

关键词： Accessibility OpenStreetMap(OSM) data quality data completeness sidewalk wheel map

An exploratory analysis of usability of Flickr tags for land use/land cover attribution

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Geo-Spatial Information Science 2019年第1期22卷 12-22页

作者： Yingwei Yan Michael Schultz Alexander zipf Institute of Geography Heidelberg UniversityHeidelbergGermany

This study explored the land use/land cover(LULC)separability by the machine-generated and user-generated Flickr photo tags(*** auto-tags and the user-tags,respectively),based on an authoritative LULC dataset for San Diego County in the United *** types of LULCs were derived from the authoritative *** was observed that certain types of the reclassified LULCs had abundant tags(*** parks)or a high tag density(*** commercial lands),compared with the less populated ones(*** agricultural lands).Certain highly weighted terms of the tags derived based on a term frequency–inverse document frequency weighting scheme were helpful for identifying specific types of the LULCs,especially for the commercial recreation lands(*** zoos).However,given the 10 sets of tags retrieved from the corresponding 10 types of LULCs,one set of tags(all the tags located at one specific type of the LULCs)could not fully delineate the corresponding LULC due to semantic overlaps,according to a latent semantic analysis.

关键词： Land use/land cover Flickr quantitative semantics volunteered geographic information

Do people communicate about their whereabouts? Investigating the relation between user-generated text messages and Foursquare check-in places

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Geo-Spatial Information Science 2018年第3期21卷 159-172页

作者： Ming Li Rene Westerholt Alexander zipf Institute of Geography Heidelberg UniversityHeidelbergGermany

The social functionality of places(***,restaurant)partly determines human behaviors and reflects a region’s functional *** descriptions of places are thus valuable to a range of studies of humans and geographic *** their potential impacts on human verbalization behaviors,one possibility is to link the functions of places to verbal representations such as users’postings in location-based social networks(LBSNs).In this study,we examine whether the heterogeneous user-generated text snippets found in LBSNs reliably reflect the semantic concepts attached with check-in *** investigate Foursquare because its available categorization hierarchy provides rich a-priori semantic knowledge about its check-in places,which enables a reliable verification of the semantic concepts identified fromuser-generated text snippets.A latent semantic analysis is conducted on a large Foursquare check-in *** results confirm that attached text messages can represent semantic concepts by demonstrating their large correspondence to the official Foursquare venue *** further elaborate the representativeness of text messages,this work also performs an investigation on the textual terms to quantify their abilities of representing semantic concepts(i.e.,representativeness),and another investigation on semantic concepts to quantify how well they can be represented by text messages(i.e.,representability).The results shed light on featured terms with strong locational characteristics,as well as on distinctive semantic concepts with potentially strong impacts on human verbalizations.

关键词： Text mining latent semantic analysis semantic concepts Foursquare location-based social network(LBSN)

Detecting repetitive structures on building footprints for the purposes of 3D modeling and reconstruction

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International Journal of Digital Earth 2017年第8期10卷 785-797页

作者： Hongchao Fan Alexander zipf Hangbin Wu Institute of Geography Heidelberg UniversityHeidelbergGermany College of Surveying and Geoinfomatics Tongji UniverisityShanghaiPeople’s Republic of China

Repetitive structures of a building share features in terms of geometries and appearance and,therefore,the 3D information for these structures can be transferred from one specification to another for the purpose of 3D modeling and reconstruction once they are identified as repetitive *** this paper,a novel approach is proposed for the detection of the repetitive structures specified by the polygons of a building’s *** of directly operating on the polygon in 2D space,the polygon is converted into a bend angle function representation in 1D space,whereby an extrusion is represented as a closed polygon intersected by the x-axis and located above it,while an intrusion is represented as a closed polygon below the *** this way,a polygon of a footprint is decomposed into a number of extrusions and intrusions which can in turn be *** task of detecting any repetitive structures specified in a building’s footprints then becomes the task of clustering the intersected polygons in the bend angle function *** extrusions/intrusions which can be placed in the same clusters can be regarded as repetitive *** show that this proposed approach can detect repetitive structures with different sizes,orientations and complexities.

关键词： GIS geometry building footprint similarity 3D modeling 3D reconstruction

Formal Definition of a User-Adaptive and Length-Optimal Routing Graph for Complex Indoor Environments

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Geo-Spatial Information Science 2011年第2期14卷 119-128页

作者： GOETZ Marcus zipf Alexander Chair of GIScience Department of GeographyUniversity of Heidelberg

Car routing solutions are omnipresent and solutions for pedestrians also ***,public or commercial buildings are getting bigger and the complexity of their internal structure has ***,the need for indoor routing solutions has *** prototypes are available,but they still lack semantically-enriched modelling (e.g.,access constraints,labels,etc.) and are not suitable for providing user-adaptive length-optimal routing in complex *** approaches consider simple rooms,concave rooms,and corridors,but important characteristics such as distinct areas in huge rooms and solid obstacles inside rooms are not considered at all,although such details can increase navigation *** formally defining a weighted indoor routing graph,it is possible to create a detailed and user-adaptive model for route *** defined graph also contains semantic information such as room labels,door accessibility constraints,***,one-way paths inside buildings are considered,as well as three-dimensional building parts,e.g.,elevators or stairways.A hierarchical structure is also possible with the presented graph model.

关键词： 3D indoor navigation 3D indoor routing city modelling formal definition routing graph buildings

The OpenStreetMap folksonomy and its evolution

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Geo-Spatial Information Science 2017年第3期20卷 219-230页

作者： Franz-Benjamin Mocnik Alexander zipf Martin Raifer Institute of Geography Heidelberg UniversityHeidelbergGermany

The comprehension of folksonomies is of high importance when making sense of Volunteered Geographic Information(VGI),in particular in the case of OpenStreetMap(OSM).So far,only little research has been conducted to understand the role and the evolution of folksonomies in VGI and OSM,which is despite the fact that without a comprehension of the folksonomies the thematic dimension of data can hardly be *** article examines the history of the OSM folksonomy,with the aim to predict its future *** particular,we explore how the documentation of the OSM folksonomy relates to its actual use in the data,and we investigate the historical and future scope and granularity of the ***,a visualization technique is proposed to examine the folksonomy in more detail.

关键词： Volunteered Geographic Information(VGI) OpenStreetMap(OSM) folksonomy taxonomy evolution granularity visualization

Routing through open spaces-A performance comparison of algorithms

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Geo-Spatial Information Science 2018年第3期21卷 247-256页

作者： Stefan Hahmann Jakob Miksch Bernd Resch Johannes Lauer Alexander zipf GIScience Research Group Institute of GeographyHeidelberg UniversityHeidelbergGermany Fraunhofer IVI Fraunhofer Institute for Transportation and Infrastructure SystemsDresdenGermany Department of Geoinformatics-Z_GIS University of SalzburgAustria Center for Geographic Analysis Harvard UniversityCambridgeMAUSA HERE GmbH&Co KG Schwalbach am TaunusGermany

Finding the shortest path through open spaces is a well-known challenge for pedestrian routing engines.A common solution is routing on the open space boundary,which causes in most cases an unnecessarily long route.A possible alternative is to create a subgraph within the open *** paper assesses this approach and investigates its implications for routing engines.A number of algorithms(Grid,Spider-Grid,Visibility,Delaunay,Voronoi,Skeleton)have been evaluated by four different criteria:(i)Number of additional created graph edges,(ii)additional graph creation time,(iii)route computation time,(iv)routing *** show that each algorithm has advantages and disadvantages depending on the use *** identify the algorithms Visibility with a reduced number of edges in the subgraph and Spider-Grid with a large grid size to be a good compromise in many scenarios.

关键词： OpenStreetMap routing open space navigation pedestrian polygon

Open-data-driven embeddable quality management services for map-based web applications

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Big Earth Data 2018年第4期2卷 395-422页

作者： Alexey Noskov Alexander zipf Institute of Geography Heidelberg UniversityHeidelbergGermany

Various map-centered web services facilitate citizens’*** applications exist for many years *** to simplification and improvement of technologies supporting WebGIS,mapbased services become more popular and important *** quality assurance for such services is a significant *** many of such applications intensively use open data,approaches focused on open solutions are *** work proposes a data-quality concept,which is based on intrinsic and comparable ***(OSM)allows intrinsic data ***,it is used as a reference dataset for quality assessment of public-sector-information Open Data *** point(EDP)-based statistics enables to filter out lowquality Open Data features.A data-type model carries out the inventory of OSM *** comparison of raster web-map tile file sizes and calculation of a simplified data quality indicator make it possible to specify acceptable data quality *** instances of quality assurance web services incorporate data features with acceptable *** work provides all required software and data for the deployment of such services under liberal *** instructions allow users to adopt the proposed solutions for their *** generic use cases illustrate the advantages of the introduced shared web services.

关键词： Data quality big spatial data WebGIS REST API computer vision