Francis Harvey

Local‐government data sharing: Evaluating the foundations of spatial data infrastructures

This paper presents a typology of local‐government data sharing arrangements in the US at a time when spatial data infrastructures (SDI) are moving into a second generation. In the first generation, the US National Spatial Data Infrastructure (NSDI) theoretically involved a pyramid of data integration resting on local‐government data sharing. Availability of local‐government data is the foundation for all SDI‐related data sharing in this model. However, first‐generation SDI data‐sharing activities and principles have gained only a tenuous hold in local governments. Some formalized data sharing occurs, but only infrequently in response to SDI programmes and policies. Previous research suggests that local‐government data sharing aligns with immediate organizational and practical concerns rather than state or national policies and programmes. We present research findings echoing extending these findings to show that local‐government data sharing is largely informal in nature and is undertaken to support existing governmental activities. NSDI principles remain simply irrelevant for the majority of surveyed local governments. The typology we present distinguishes four distinct types of local‐government data sharing arrangements that reflect institutional, political, and economic factors. The effectiveness of second generation, client‐service‐based SDI will be seriously constrained if the problems of local government take‐up fail to be addressed.

To Volunteer or to Contribute Locational Information? Towards Truth in Labeling for Crowdsourced Geographic Information

Geographers, planners, and others increasingly refer to crowdsourced data in geography as volunteered geographic information (VGI). But is volunteered the right adjective to use for all types of crowdsourced geographic information? This chapter examines this question by making the following distinction along an ethical line for crowdsourced data collection: data collected following an “opt-in” agreement is volunteered; data collected under an “opt-out” provision is contributed (CGI). Opt-in agreements provide some clarity and control in the collection and intended reuse of collected data. Opt-out agreements are, in comparison, very open-ended and begin with few, if any, possibilities to control data collection. The chapter suggests that distinguishing contributed crowdsourced data from volunteered crowdsourced data is important to start to understand the nature of sources of crowdsourced data of any provenance and to help begin to identify possible biases. In the concluding discussion, this chapter argues that the simple distinction between CGI and VGI is valuable for assessments of data’s fitness for use. Following the truth-in-labeling principle known for food products, differentiating between CGI and VGI is also helpful to identify cases where lax approaches or even malfeasance leads to inaccurate or biased crowdsourced data.

The Imbrication of Geography and Technology: The Social Construction of Geographic Information Systems

This chapter examines the disciplinary interface between geography and technology from an ecological perspective. Our analysis of a few cases shows that the relationships between geography and technology are never clear-cut, but always intertwined like tree roots in a forest. The roots (or rhizomes) of each tree support an individual above ground, while the tangled roots just visible or invisible below the surface are a messy tangle that also are part of biochemical processes that sustain each tree, and the forest in which other trees grow. Rhizomes from different trees and plants interweave in symbiotic or parasitic relationship that are integral to the ecosystem. The relationships between geography and technology also can be understood in this ecological metaphor. What has made the growth of GIS possible? We argue that a highly fertile interface between geography and technology supports the profuse growth of GIS. Drawing on science and technology studies, we argue that the geography-technology relationship is no “chicken and egg” problem, but is evidenced in myriad, theoretically infinite relationships and interactions occurring worldwide. Each GIS implementation follows many roots, and we need to excavate them in order to understand the historical development of the interface between geography and technology. This approach calls for attention to specific sites and configurations of technology. The development of geography is intricately interwoven with the development of technology, but under no circumstances does technology determine a path for geography. In the fillamous rhizomatic network, many geographies and technologies connect and lead to subsequent developments.

Designing for Interoperability: Overcoming Semantic Differences

Interoperability can be understood in a number of ways. In a minimal sense, even the capability to transfer data from one computer system to another without transformation loss can be identified as interoperability. In a broader sense, interoperability can be taken to suggest the ability of different applications to interact dynamically, facilitating the smooth interface of multiple information sources. This chapter examines interoperability in this second sense, specifically the role of semantics in facilitating the exchange of information.

Summarizing trajectories into k -primary corridors: a summary of results

Given a set of GPS trajectories on a road network, the goal of the k-Primary Corridors (k-PC) problem is to summarize trajectories into k groups, each represented by its most central trajectory. This problem is important to a variety of domains, such as transportation services interested in finding primary corridors for public transportation or greener travel (e.g., bicycling) by leveraging emerging GPS trajectory datasets. Related trajectory mining approaches, e.g., density or frequency based hot-routes, focus on anomaly detection rather than summarization and may not be effective for the k-PC problem. The k-PC problem is challenging due to the computational cost of creating the track similarity matrix. A naïve graph-based approach to compute a single element of this track similarity matrix requires multiple invocations of common shortest-path algorithms (e.g., Dijkstra). To reduce the computational cost of creating this track similarity matrix, we propose a novel algorithm that switches from a graph-based view to a matrix-based view, computing each element in the matrix with a single invocation of a shortest-path algorithm. Experimental results show that these ideas substantially reduce computational cost without altering the results.

Improving Multi-Purpose GIS Design: Participative Design

Crucial to the design of multi-purpose GIS is the identification of semantical differences and commonalties between the concepts held by participants. Design involves communication between the diverse groups of participants as they mitigate their differences, find common understandings, and find coherency. It is a process of negotiating semantics.

Extending the Classroom: Hypermedia-supported Learning

ABSTRACT Hypermedia materials have great potential in teaching but it is unclear how university geography courses will adapt to the new technology and evolve. We have used a two-pronged approach that places course-specific materials into an integrated hypermedia resource connected to external sources that complement and extend the content. This strategy provides a path for traditional course materials to give access to the enormous resources available on the Worldwide Web. The results of a student survey indicate that the hypermedia materials are a helpful addition for students, especially to support individual learning strategies.

From Geographic Holism to Geographic Information System

Substantial changes in a core idea of geography, integration, have occurred since Alexander von Humboldt published Kosmos (1845-1862). These changes are part of a larger shift in Western civilization to mechanistic reasoning. This shift led to the strengthening of system-based analysis, central to the development of geographic information systems (GIS). The duality of holism and the systems approach has led to an apparent contradiction in geography. R. Hartshorne in The Nature of Geography described this contradiction, but as did Alfred Hettner and Emil Wisotzki before, moved to partial systems as the core concept of geographic integration. Hartshornes concept of vertical integration is the antecedent for the ubiquitous GIS layer model. The reduction of geographic relationships and processes to mechanistic components (layers) aids the systematic approach, but may lessen geographic understanding of a places interrelationships. Although the partiality of the system approach was already acknowledged by Fin...

Fast and exact network trajectory similarity computation: a case-study on bicycle corridor planning

Given a set of trajectories on a road network, the goal of the All-Pair Network Trajectory Similarity (APNTS) problem is to calculate the similarity between all trajectories using the Network Hausdorff Distance. This problem is important for a variety of societal applications, such as facilitating greener travel via bicycle corridor identification. The APNTS problem is challenging due to the high cost of computing the exact Network Hausdorff Distance between trajectories in spatial big datasets. Previous work on the APNTS problem takes over 16 hours of computation time on a real-world dataset of bicycle GPS trajectories in Minneapolis, MN. In contrast, this paper focuses on a scalable method for the APNTS problem using the idea of row-wise computation, resulting in a computation time of less than 6 minutes on the same datasets. We provide a case study for transportation services using a data-driven approach to identify primary bicycle corridors for public transportation by leveraging emerging GPS trajectory datasets.

Spatial Cyberinfrastructure: Building New Pathways for Geospatial Semantics on Existing Infrastructures

Spatial data infrastructures (SDI), with technological and conceptual roots stretching back multiple decades, are moving into a new era through the development of spatial cyberinfrastructures (spatial CI) that account for geospatial semantics. While the technology and concepts share many similarities, spatial cyberinfrastructures distinctly focus on the provision of information to support scientific knowledge sharing. These cyberinfrastructures are increasingly connected into an ecology of scientific knowledge sharing based on the formalization of geospatial semantics and support for shared knowledge and collective intelligence. We trace the development of cyberinfrastructures from spatial data infrastructures as the potential framework for geospatial semantical interoperability. The chapter also points to substantial semantic research challenges and the potential of spatial cyberinfrastructures.