Table 1 Metrics used in this study, along with their definitions and resolutions provided by Facebook
Metric | Units | Definition | Spatial resolution provided by Facebook | Temporal resolution provided by Facebook |
|---|---|---|---|---|
Population density | Number of Facebook users | Average number of Facebook users within a Bing tile during an 8Â h period | Bing tile level 13 and 16 | 8Â h |
Population flows | Number of Facebook users | Number of Facebook users that shared the same modal tile across two adjacent 8Â h time periods | Bing tile level 12 | 8Â h |
Distance travelled* | Kilometres | Total distance between tile centroids ‘travelled’ by Facebook users across two adjacent 8 h time periods | Bing tile level 12 | 8 h |
Co-location | – | Probability of two Facebook users from varying Pitney-Bowes administrative regions are present within the same level 16 Bing tile during a random 5-min bin | Pitney-Bowes administrative regions | Weekly |
International movement | Number of Facebook users | Number of Facebook users moving between two countries within a single day | Country | Daily |