A Framework for Quality Evaluation of VGI linear datasets

Spatial data collection, processing, distribution and understanding have traditionally been handled by professionals. However, as technology advances, non-experts can now collect Geographic Information (GI), create spatial databases and distribute GI through web applications. This Volunteered Geographic Information (VGI), as it is called, seems to be a promising spatial data source. However, the most concerning issue is its unknown and heterogeneous quality, which cannot be handled by traditional quality measurement methods; the quality elements that these methods measure were standardised long before the appearance of VGI and they assume uniform quality behaviour. The lack of a suitable quality evaluation framework with an appropriate level of automation, which would enable the repetition of the quality assessment when VGI is updated, renders the choice of using it difficult or risky for potential users. This thesis proposes a framework for quality evaluation of linear VGI datasets, used to represent networks. The suggested automated methodology is based on a comparison of a VGI dataset with a dataset of known quality. The heterogeneity issue is handled by producing individual results for small areal units, using a tessellation grid. The quality elements measured are data completeness, attribute and positional accuracy, considered as most important for VGI. Compared to previous research, this thesis includes an automated data matching procedure, specifically designed for VGI. It combines geometric and thematic constraints, shifting the scale of importance from geometry to non-spatial attributes, depending on their existence in the VGI dataset. Based on the data matching results, all quality elements are then measured for corresponding objects, providing a more accurate quality assessment. The method is tested on three case studies. Data matching proves to be quite efficient, leading to more accurate quality results. The data completeness approach also tackles VGI over-completeness, which broadens the method usage for data fusion purposes

The National Map

The National Map is an online, interactive map service published by the United States Geological Survey (USGS). Users can create and print high-resolution shaded relief maps of a local area, a state, or the entire U.S. A variety of data layers are available, including administrative boundaries, geographic names, geology, and land use/land cover. The 'Find Place' tool allows users to find a location anywhere in the United States using latitude and longitude, U.S. National Grid coordinates, Universal Transverse Mercator (UTM) coordinates, or a place name. The 'Identify' tool allows users to obtain the coordinates of any point in the U.S. Educational levels: Middle school, High school, Undergraduate lower division

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

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

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

Open-Source, Open-Architecture SoftwarePlatform for Plug-InElectric Vehicle SmartCharging in California

This interdisciplinary eXtensible Building Operating System–Vehicles project focuses on controlling plug-in electric vehicle charging at residential and small commercial settings using a novel and flexible open-source, open-architecture charge communication and control platform. The platform provides smart charging functionalities and benefits to the utility, homes, and businesses.This project investigates four important areas of vehicle-grid integration research, integrating technical as well as social and behavioral dimensions: smart charging user needs assessment, advanced load control platform development and testing, smart charging impacts, benefits to the power grid, and smart charging ratepayer benefits

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

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

Towards a Protocol for the Collection of VGI Vector Data

A protocol for the collection of vector data in Volunteered Geographic Information (VGI) projects is proposed. VGI is a source of crowdsourced geographic data and information which is comparable, and in some cases better, than equivalent data from National Mapping Agencies (NMAs) and Commercial Surveying Companies (CSC). However, there are many differences in how NMAs and CSC collect, analyse, manage and distribute geographic information to that of VGI projects. NMAs and CSC make use of robust and standardised data collection protocols whilst VGI projects often provide guidelines rather than rigorous data collection specifications. The proposed protocol addresses formalising the collection and creation of vector data in VGI projects in three principal ways: by manual vectorisation; field survey; and reuse of existing data sources. This protocol is intended to be generic rather than being linked to any specific VGI project. We believe that this is the first protocol for VGI vector data collection that has been formally described in the literature. Consequently, this paper shall serve as a starting point for on-going development and refinement of the protocol

Understanding design with VGI using an information relevance framework

Volunteered Geographic Information (VGI) has the potential to offer increased value and usability benefits to end-users over and above that of Professional Geographic Information (PGI). Using a multi-methods approach consisting of participatory observation, focus groups and diary studies, the differences between VGI and PGI are investigated in relation to the characteristics which are the most, or least relevant to an end-user community. The key finding was that the discussion amongst designers should not be whether to choose VGI or PGI as the information data set, but to consider which combination of VGI and PGI relating to different geographic features and task characteristics will best fit the user requirements. VGI is likely to be most relevant to the user when a geographic features is dynamic rather than static in nature These findings have implications for how different forms of information may be most effectively utilised within different usage situations. Above all, a case is presented for the implementation of User Centred Design principals when integrating VGI and PGI together in a single mashup based product to maximise benefit to the end user