Alexander Savelyev

SensePlace2: GeoTwitter analytics support for situational awareness

Geographically-grounded situational awareness (SA) is critical to crisis management and is essential in many other decision making domains that range from infectious disease monitoring, through regional planning, to political campaigning. Social media are becoming an important information input to support situational assessment (to produce awareness) in all domains. Here, we present a geovisual analytics approach to supporting SA for crisis events using one source of social media, Twitter. Specifically, we focus on leveraging explicit and implicit geographic information for tweets, on developing place-time-theme indexing schemes that support overview+detail methods and that scale analytical capabilities to relatively large tweet volumes, and on providing visual interface methods to enable understanding of place, time, and theme components of evolving situations. Our approach is user-centered, using scenario-based design methods that include formal scenarios to guide design and validate implementation as well as a systematic claims analysis to justify design choices and provide a framework for future testing. The work is informed by a structured survey of practitioners and the end product of Phase-I development is demonstrated / validated through implementation in SensePlace2, a map-based, web application initially focused on tweets but extensible to other media.

Geo-Located Tweets. Enhancing Mobility Maps and Capturing Cross-Border Movement

Capturing human movement patterns across political borders is difficult and this difficulty highlights the need to investigate alternative data streams. With the advent of smart phones and the ability to attach accurate coordinates to Twitter messages, users leave a geographic digital footprint of their movement when posting tweets. In this study we analyzed 10 months of geo-located tweets for Kenya and were able to capture movement of people at different temporal (daily to periodic) and spatial (local, national to international) scales. We were also able to capture both long and short distances travelled, highlighting regional connections and cross-border movement between Kenya and the surrounding countries. The findings from this study has broad implications for studying movement patterns and mapping inter/intra-region movement dynamics.

Volunteered geographic services: developing a linked data driven location-based service

The term Volunteered Geographic Information (VGI) describes various layperson-based, geo-collaboration projects to collect, maintain, and visualize information. VGI has been successfully utilized in scenarios such as emergency response and is also increasingly integrated into commercial products. Based on an analysis of existing projects and research, we propose to extend the idea of VGI by introducing Volunteered Geographic Services (VGS). Instead of contributing information, volunteers can request or offer microservices to their local community. We provide a flexible server framework that handles service requests and offers. We also implement a smartphone application developed using Googles Android platform. The server and mobile client are realized following the Linked Data paradigm and using Semantic Web technologies. In this paper, we discuss the idea behind VGS, motivate it using two scenarios, and explain the technical realization.