“…Wood et al (2013) proposed the metric of user-day to estimate visitation rate at recreational sites with Flickr SMD; the authors found this metric to be a good proxy for empirical visitation rates. With this metric, the possibility of using SMD source as a reliable proxy for visitation was demonstrated by statistical correlation and regression analysis methods, including simple nonlinear regressions (Arkema et al , 2021), Spearman's and Pearson's correlation tests (Ghermandi et al , 2020; Wilkins et al , 2021), linear regressions (Zhang et al , 2021), ordinary least squares regressions (Ghermandi et al , 2020), multiple regressions (Sessions et al , 2016), generalized linear models and wavelet analysis (Mancini et al , 2018). The databases of Flickr (Arkema et al , 2021; Wilkins et al , 2021), Instagram (Heikinheimo et al , 2017; Wood et al , 2020) and Twitter (Sim and Miller, 2019; Ghermandi et al , 2020) were most frequently used as SMD sources in the previous studies.…”