Horizontal positional accuracy of Google Earth's imagery over rural areas: a study case in Tamaulipas, Mexico

Due to the popularity of Google Earth (GE), users commonly assume that it is a credible and accurate source of information. Consequently, GE's imagery is frequently used in scientific and others projects. However, Google states that data available in their geographic products are only approximations and, therefore, their accuracy is not officially documented. In this paper, the horizontal positional accuracy of GE's imagery is assessed by means of comparing coordinates extracted from a rural cadastral database against coordinates extracted from well-defined and inferred check points in GE's imagery. The results suggest that if a large number of well-defined points are extracted from areas of high resolution imagery, GE's imagery over rural areas meets the horizontal accuracy requirements of the ASPRS for the production of "Class 1" 1:20,000 maps. Nonetheless, the results also show that georegistration and large horizontal errors occur in GE's imagery. Consequently, despite its overall horizontal positional accuracy, coordinates extracted from GE's imagery should be used with caution

Discovery and integration of Web 2.0 content into geospatial information infrastructures: a use case in wild fire monitoring

Efficient environment monitoring has become a major concern for society to guarantee sustainable development. For instance, forest fire detection and analysis is important to provide early warning systems and identify impact. In this environmental context, availability of up-to-date information is very important for reducing damages caused. Environmental applications are deployed on top of GeospatialInformation Infrastructures (GIIs) to manage information pertaining to our environment. Suchinfrastructures are traditionally top-down infrastructures that do not consider user participation. This provokes a bottleneck in content publication and therefore a lack of content availability. On the contrary mainstream IT systems and in particular the emerging Web 2.0 Services allow active user participation that is becoming a massive source of dynamic geospatial resources. In this paper, we present a webservice, that implements a standard interface, offers a unique entry point for spatial data discovery, both in GII services and web 2.0 services. We introduce a prototype as proof of concept in a forest fire scenario, where we illustrate how to leverage scientific data and web 2.0 conten

Facebook in the university workplace

Access to social network sites (SNS) in the workplace has been much debated. While some consider SNS a distraction, others consider them a tool for professional socialisation and that recreational access positively impacts satisfaction. This exploratory study reports results from an online survey of employees from one faculty of an Australian university, exploring how they used Facebook at work and how they would react to a hypothetical Facebook ban. Three-quarters of respondents used Facebook at work, primarily for personal socialisation during breaks. Many self-imposed a strict personal/professional separation, but opposed a hypothetical SNS ban, perceiving it as an infringement on their workplace autonomy. It is argued that university employees - academic and professional - can be trusted to self-regulate access

A Survey of Geo-tagged Multimedia Content Analysis within Flickr

Part 2: MHDW WorkshopInternational audienceOur survey paper attempts to investigate how recent and undoubted emerge in enriched, geo-tagged social networks’ multimedia content sharing works to the benefit of their users and whether it could be handled in a formal way, in order to capture the meaningful semantics rising from this newly introduced user experience. It further specializes its focus by providing an overview of current state-of-the-art techniques with respect to geo-tagged content access, processing and manipulation within the popular Flickr social network. In this manner it explores the role of information retrieval, integration and extraction from the technical point of view, coupled together with human social network activities, like, for instance, localization and recommendations based on pre-processed collaborative geo-tagged photos, resulting into more efficient, optimized search results

Trust in News Media: Development and Validation of a Multidimensional Scale

The dimensions that individuals apply in evaluating the trustworthiness or credibility of news media bear great theoretical and practical relevance. In previous research, however, there is no standardized scale for the measurement of trust in news media. Thus, the purpose of this article is to present the development and validation of a multidimensional scale of trust in news media. A theoretically derived model is tested on a representative sample via confirmatory factor analysis. After some modifications, the model is then validated on another independent sample. These results confirm the hypothesis that trust in news media can be considered a hierarchical factor (of second order) that consists of four lower order factors, including trust in the selectivity of topics, trust in the selectivity of facts, trust in the accuracy of depictions, and trust in journalistic assessment. This model is the first validated scale of trust in news media in communication research

Comparing expert and non-expert conceptualisations of the land: An analysis of crowdsourced land cover data

This research compares expert and non-expert conceptualisations of land cover data collected through a Google Earth web-based interface. In so doing it seeks to determine the impacts of varying landscape conceptualisations held by different groups of VGI contributors on decisions that may be made using crowdsourced data, in this case to select the best global land cover dataset in each location. Whilst much other work has considered the quality of VGI, as yet little research has considered the impact of varying semantics and conceptualisations on the use of VGI in formal scientific analyses. This study found that conceptualisation of cropland varies between experts and non-experts. A number of areas for further research are outlined