The Spatial-Comprehensiveness (S-COM) Index: Identifying Optimal Spatial Extents in Volunteered Geographic Information Point Datasets

Abstract

Social media and other forms of volunteered geographic information (VGI) are used frequently as a source of fine-grained big data for research. While employing geographically referenced social media data for a wide array of purposes has become commonplace, the relevant scales over which these data apply to is typically unknown. For researchers to use VGI appropriately (e.g., aggregated to areal units (e.g., neighbourhoods) to elicit key trend or demographic information), general methods for assessing the quality are required, particularly, the explicit linkage of data quality and relevant spatial scales, as there are no accepted standards or sampling controls. We present a data quality metric, the Spatial-comprehensiveness Index (S-COM), which can delineate feasible study areas or spatial extents based on the quality of uneven and dynamic geographically referenced VGI. This scale-sensitive approach to analyzing VGI is demonstrated over different grains with data from two citizen science initiatives. The S-COM index can be used both to assess feasible study extents based on coverage, user-heterogeneity, and density and to find feasible sub-study areas from a larger, indefinite area. The results identified sub-study areas of VGI for focused analysis, allowing for a larger adoption of a similar methodology in multi-scale analyses of VGI.

The Geographies of Expatriates’ Cultural Venues in Globalizing Shanghai: A Geo-Information Approach Applied to Social Media Data Platform

“…The purpose of this paper was to analyze the geographies of cultural venues frequently used by expatriates in a globalizing Shanghai. To this end, we used state-of-the-art data and methods put forward in the science and technology of geographic information [1][2][3][4][5][6][7][8][9][10]. Expatriates living in Shanghai constitute a diverse, highly skilled, and mobile workforce [11], and recent research highlights that the presence of this community is both a sign and an enabler of the myriad processes underlying global city development [12][13][14].…”