I am hosting a conference and want to show a map of where the attendees have arrived from. I have an input file with the names of the cities. I'd like to put a dot on each city, and have the size of the dot be proportional to the number of attendees. So my input looks like this:
Chicago 10 Philadelphia 20 New York 5 San Francisco 25
I'd like to do this with Python, which I believe means I should be using matplotlib and basemap. I've found sample code that has shapefiles for the US, but it's not clear to me how to get the lat/lon data US cities. Do I have to implement this all from scratch? It seems like a fairly common thing to do.