1,858 research outputs found

    Are crowdsourced datasets suitable for specialized routing services? Case study of Openstreetmap for routing of people with limited mobility

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    Nowadays, Volunteered Geographic Information (VGI) has increasingly gained attractiveness to both amateur users and professionals. Using data generated from the crowd has become a hot topic for several application domains including transportation. However, there are concerns regarding the quality of such datasets. As one of the most famous crowdsourced mapping platforms, we analyze the fitness for use of OpenStreetMap (OSM) database for routing and navigation of people with limited mobility. We assess the completeness of OSM data regarding sidewalk information. Relevant attributes for sidewalk information such as sidewalk width, incline, surface texture, etc. are considered, and through both extrinsic and intrinsic quality analysis methods, we present the results of fitness for use of OSM data for routing services of disabled persons. Based on empirical results, it is concluded that OSM data of relatively large spatial extents inside all studied cities could be an acceptable region of interest to test and evaluate wheelchair routing and navigation services, as long as other data quality parameters such as positional accuracy and logical consistency are checked and proved to be acceptable. We present an extended version of OSMatrix web service and explore how it is employed to perform spatial and temporal analysis of sidewalk data completeness in OSM. The tool is beneficial for piloting activities, whereas the pilot site planners can query OpenStreetMap and visualize the degree of sidewalk data availability in a certain region of interest. This would allow identifying the areas that data are mostly missing and plan for data collection events. Furthermore, empirical results of data completeness for several OSM data indicators and their potential relation to sidewalk data completeness are presented and discussed. Finally, the article ends with an outlook for future research study in this area

    Analyzing the Tagging Quality of the Spanish OpenStreetMap

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    In this paper, a framework for the assessment of the quality of OpenStreetMap is presented, comprising a batch of methods to analyze the quality of entity tagging. The approach uses Taginfo as a reference base and analyses quality measures such as completeness, compliance, consistence, granularity, richness and trust . The framework has been used to analyze the quality of OpenStreetMap in Spain, comparing the main cities of Spain. Also a comparison between Spain and some major European cities has been carried out. Additionally, a Web tool has been also developed in order to facilitate the same kind of analysis in any area of the world

    Quality Assessment of the Canadian OpenStreetMap Road Networks

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    Volunteered geographic information (VGI) has been applied in many fields such as participatory planning, humanitarian relief and crisis management because of its cost-effectiveness. However, coverage and accuracy of VGI cannot be guaranteed. OpenStreetMap (OSM) is a popular VGI platform that allows users to create or edit maps using GPS-enabled devices or aerial imageries. The issue of geospatial data quality in OSM has become a trending research topic because of the large size of the dataset and the multiple channels of data access. The objective of this study is to examine the overall reliability of the Canadian OSM data. A systematic review is first presented to provide details on the quality evaluation process of OSM. A case study of London, Ontario is followed as an experimental analysis of completeness, positional accuracy and attribute accuracy of the OSM street networks. Next, a national study of the Canadian OSM data assesses the overall semantic accuracy and lineage in addition to the quality measures mentioned above. Results of the quality evaluation are compared with associated OSM provenance metadata to examine potential correlations. The Canadian OSM road networks were found to have comparable accuracy with the tested commercial database (DMTI). Although statistical analysis suggests that there are no significant relations between OSM accuracy and its editing history, the study presents the complex processes behind OSM contributions possibly influenced by data import and remote mapping. The findings of this thesis can potentially guide cartographic product selection for interested parties and offer a better understanding of future quality improvement in OSM

    Recent Developments and Future Trends in Volunteered Geographic Information Research: The Case of OpenStreetMap

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    User-generated content (UGC) platforms on the Internet have experienced a steep increase in data contributions in recent years. The ubiquitous usage of location-enabled devices, such as smartphones, allows contributors to share their geographic information on a number of selected online portals. The collected information is oftentimes referred to as volunteered geographic information (VGI). One of the most utilized, analyzed and cited VGI-platforms, with an increasing popularity over the past few years, is OpenStreetMap (OSM), whose main goal it is to create a freely available geographic database of the world. This paper presents a comprehensive overview of the latest developments in VGI research, focusing on its collaboratively collected geodata and corresponding contributor patterns. Additionally, trends in the realm of OSM research are discussed, highlighting which aspects need to be investigated more closely in the near future

    A grounding-based ontology of data quality measures

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    Data quality and fitness for purpose can be assessed by data quality measures. Existing ontologies of data quality dimensions reflect, among others, which aspects of data quality are assessed and the mechanisms that lead to poor data quality. An understanding of which source of information is used to judge about data quality and fitness for purpose is, however, lacking. This article introduces an ontology of data quality measures by their grounding, that is, the source of information to which the data is compared to in order to assess their quality. The ontology is exemplified with several examples of volunteered geographic information (VGI), while also applying to other geographical data and data in general. An evaluation of the ontology in the context of data quality measures for OpenStreetMap (OSM) data, a well-known example of VGI, provides insights about which types of quality measures for OSM data have and which have not yet been considered in literature

    Assessing the accuracy of openstreetmap data in south africa for the purpose of integrating it with authoritative data

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    Includes bibliographical references.The introduction and success of Volunteered Geographic Information (VGI) has gained the interest of National Mapping Agencies (NMAs) worldwide. VGI is geographic information that is freely generated by non-experts and shared using VGI initiatives available on the Internet. The NMA of South Africa i.e. the Chief Directorate: National Geo- Spatial Information (CD: NGI) is looking to this volunteer information to maintain their topographical database; however, the main concern is the quality of the data. The purpose of this work is to assess whether it is feasible to use VGI to update the CD: NGI topographical database. The data from OpenStreetMap (OSM), which is one the most successful VGI initiatives, was compared to a reference data set provided by the CD: NGI. Corresponding features between the two data sets were compared in order to assess the various quality aspects. The investigation was split into quantitative and qualitative assessments. The aim of the quantitative assessments was to determine the internal quality of the OSM data. The internal quality elements included the positional accuracy, geometric accuracy, semantic accuracy and the completeness. The _rst part of the qualitative assessment was concerned with the currency of OSM data between 2006 and 2012. The second part of the assessment was focused on the uniformity of OSM data acquisition across South Africa. The quantitative results showed that both road and building features do not meet the CD: NGI positional accuracy standards. In some areas the positional accuracy of roads are close to the required accuracy. The buildings generally compare well in shape to the CD: NGI buildings. However, there were very few OSM polygon features to assess, thus the results are limited to a small sample. The semantic accuracy of roads was low. Volunteers do not generally classify roads correctly. Instead, many volunteers prefer to class roads generically. The last part of the quantitative results, the completeness, revealed that commercial areas reach high completeness percentages and sometimes exceed the total length of the CD: NGI roads. In residential areas, the percentages are lower and in low urban density areas, the lowest. Nonetheless, the OSM repository has seen signi_cant growth since 2006. The qualitative results showed that because the OSM repository has continued to grow since 2006, the level of currency has increased. In South Africa, the most contributions were made between 2010 and 2012. The OSM data set is thus current after 2012. The amount and type of contributions are however not uniform across the country for various reasons. The number of point contributions was low. Thus, the relationship between the type of contribution and the settlement type could not be made with certainty. Because the OSM data does not meet the CD: NGI spatial accuracy requirements, the two data sets cannot be integrated at the database level. Instead, two options are proposed. The CD: NGI could use the OSM data for detecting changes to the landscape only. The other recommendation is to transform and verify the OSM data. Only those features with a high positional accuracy would then be ingested. The CD: NGI currently has a shortage of sta_ that is quali_ed to process ancillary data. Both of the options proposed thus require automated techniques because it is time consuming to perform these tasks manually

    An Analysis of Quality for Volunteered Geographic Information

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    In recent years there has been a growing number of online user communities engaged in the creation, visualization, and use of volunteered geographic information (VGI). These data may represent an untapped resource for researchers analyzing large-area geographic phenomena such as species distributions patterns or land and resource management issues. However very few studies have used VGI for analytic research questions as little is known about the quality of these data. An understanding of the validity of VGI is a prerequisite for further exploitation of these novel data sources in research contexts. This paper looks to identify key issues related to the credibility of VGI through a critical literature review. If the measurement of data quality for volunteered geographic data can be established in a formal framework, many new sources of information that could potentially be used to answer cross-cutting geographic research questions of interest to established communities. This low cost alternative to traditional sources of data can be used for up-to-date geographic information, if the data can be trusted

    Modeling aggregated expertise of user contributions to assess the credibility of OpenStreetMap features + Erratum

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    The emergence of volunteered geographic information (VGI) during the past decade has fueled a wide range of research and applications. The assessment of VGI quality and fitness-of-use is still a challenge because of the non-standardized and crowdsourced data collection process, as well as the unknown skill and motivation of the contributors. However, the frequent approach of assessing VGI quality against external data sources using ISO quality standard measures is problematic because of a frequent lack of available external (reference) data, and because for certain types of features, VGI might be more up-to-date than the reference data. Therefore, a VGI-intrinsic measure of quality is highly desirable. This study proposes such an intrinsic measure of quality by developing the concept of aggregated expertise based on the characteristics of a feature's contributors. The article further operationalizes this concept and examines its feasibility through a case study using OpenStreetMap (OSM). The comparison of model OSM feature quality with information from a field survey demonstrates the successful implementation of this novel approach

    Usability of VGI for validation of land cover maps

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    Volunteered Geographic Information (VGI) represents a growing source of potentially valuable data for many applications, including land cover map validation. It is still an emerging field and many different approaches can be used to take value from VGI, but also many pros and cons are related to its use. Therefore, since it is timely to get an overview of the subject, the aim of this article is to review the use of VGI as reference data for land cover map validation. The main platforms and types of VGI that are used and that are potentially useful are analysed. Since quality is a fundamental issue in map validation, the quality procedures used by the platforms that collect VGI to increase and control data quality are reviewed and a framework for addressing VGI quality assessment is proposed. A review of cases where VGI was used as an additional data source to assist in map validation is made, as well as cases where only VGI was used, indicating the procedures used to assess VGI quality and fitness for use. A discussion and some conclusions are drawn on best practices, future potential and the challenges of the use of VGI for land cover map validation

    A Planning based Evaluation of Spatial Data Quality of OpenStreetMap Building Footprints in Canada

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    OpenStreetMap (OSM) is an editable world map where users can create and retrieve data. Building footprints are an OSM dataset that is of particular interest, as this data has many useful applications for planners and academic professionals. Measuring the spatial data quality of OSM building footprints remains a challenge as there are numerous quality measures that can be used and existing studies have focused on other OSM datasets or rather a single quality measure. The study performed in this thesis developed a set of ArcGIS models to test numerous spatial data quality measures for OSM building footprints in a sample of mid-sized Canadian municipalities and gain a comprehensive understanding of spatial data quality. The models performed tests by comparing to municipal datasets as well as determining other quality measures without a reference dataset. The results of this study found that the overall spatial data quality of OSM building footprints varies across mid-sized municipalities in Canada. There is no link between a municipality’s location or perceived importance and the level of spatial data quality. The study also found that commercial areas have a higher level of completeness than residential areas. While the models worked well to test numerous spatial data quality measures for building footprints and can be used by others on other building footprint datasets, there exist some limitations. Certain tests that identify potential building footprint errors need to be checked to see if they are indeed errors. Also, the models were not able to measure any aspect of shape metrics. Suggestions for further studies include measuring shape metrics of building footprints from OSM as well as encouraging and subsequently monitoring OSM contributions in a particular area
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