I assume that these companies have obtained/collected/bought raw vector data and then have used a GIS software package and some custom cartography workflows to produce maps with good symbology/layout and then cached them into multiple tiles.
Rasterizing vectors into tiles is not that particularly interesting, but I was often wondering what kind of Desktop GIS software have those large companies used to make those maps? Esri, for instance, uses ArcGIS platform for making the Esri basemaps such as Esri World Street Map.
What desktop GIS software do Google and Microsoft use for creating maps? I am curious about that because I want to know what other GIS packages apart from Esri ArcGIS are capable of doing this work on such a large scale.