This map of the Tucson area is an approximation of rental properties prepared by Inside Airbnb, a New York City-based nonprofit that tracks the vacation rental industry using data electronically extracted from the public websites of rental firms. The sites shown are approximate because companies don’t publicly disclose the addresses of rental units, only their general locations. Inside Airbnb’s data is one of the few public sources available on the industry, and is deemed reliable enough that universities use it in their research.