I've been asked to do some research where I compare survey data to some population numbers. Unfortunately, I think it is likely the case that people who live in smaller cities that are close to large cities may have supplied the name of the larger city. I currently have city-level population data.
Is there a way to map nearby cities into larger urban agglomerates at a global level? I'd be open to simple solutions, like a mapping table, or complex solutions, such as something that considers proximity or other data sources to connect cities.