Here's Brooklyn (you can link to the originals to click on and identify each dot):
And San Francisco:
The idea behind these maps is that coffee shops -- and independent ones in particular -- signal the existence of certain kinds of places, as the creators describe it:
Independent coffee shops are positive markers of a living community. They function as social spaces, urban offices, and places to see the world go by. Communities are often formed by having spaces in which people can have casual interactions, and local and walkable coffee shops create those conditions, not only in the coffee shop themselves, but on the sidewalks around them. We use maps to know where these coffee shop communities exist and where, by placing new coffee shops, we can help form them.
Coffee shops are unlike other community assets in that they enable us to mingle with strangers in ways that we might not in restaurants, to meet a wider range of people than we would in a bar, to linger in ways that we don't at the grocery store, or to people-watch with an ease that would be awkward almost anywhere else.
That's not to say that coffee shops are the only places that potentially create such community (nor that they serve this function in all communities). But if high-end restaurants and organic groceries are signs of areas with a lot of literal capital, independent coffee shops are one plausible indicator of social capital.