What non-Google Ads signals are used to model shop visits?

Google uses aggregated and anonymized GPS, Wi-Fi, and network data from a vast number of opted-in, signed-in users to model shop visits. This data provides insights into foot traffic patterns and helps attribute online ad interactions to offline store visits. While third-party vendors might offer similar data, Google primarily relies on its own extensive data sources for this modeling. Interaction with location extensions or online ads followed by a shop visit are signals within Google Ads that help measure shop visits, but they are not the underlying non-Google Ads data used for the broader modeling of foot traffic and visit patterns.