Zoom Levels

Google Maps API describes the approximate level of detail at each zoom level: World 1, Landmass/continent 5, City 10, Streets 15, Buildings 20. Mapstraction describes zoom levels trough geographic descriptions like this: World 0/1 , Country 4, State 7, City 13, Street 16.

See also:

• https://wiki.openstreetmap.org/wiki/Zoom_levels
• http://www.gretchenpeterson.com/blog/archives/3260
• https://blogs.esri.com/esri/arcgis/2017/05/19/web-map-zoom-levels-updated/
• https://gis.stackexchange.com/questions/7430/what-ratio-scales-do-google-maps-zoom-levels-correspond-to