I'm basically trying to duplicate broadbandmap.gov and how you can enter a zip code and return local broadband providers for a project. I downloaded their data files here. They use census blocks to identify locations. Then if you search by zip code or city, they say, "The list above only displays the broadband providers offering service in the Census Block that is in the center of your search results. The results do not display a summary of the search area, only the center of the search. For example, if you search for a city name only, then the search would return the approximate center of that city and only the information in the Census Block at the center of the city would be displayed."
How do I convert this data from census block to geo-center of zip code? Is there a resource available somewhere?