I'm incredibly new to creating these types of maps, but I'm trying to create a coverage map not unlike the cell companies show their coverage. Our database simply has lists of ZIP codes that our service covers and I want to display these on a map, colored in, like the cell phone companies do.
I have figured out how to do this on my own (using QGIS and joining my CSV list with the shapefile from the USPS of zip codes)... But the thing I can't figure out how to do is to show a radius around each zip coded area. Our coverage extends 100 miles (50 miles in each direction) from the center point of each zip code.
With a list of over 32,000 zip codes, is there a way to easily extend the coloring area around each zip code to include this extra area?