How to best display voting map
I have a very simple, rather standard setup: Users vote yes or no on something, and I want to display a map of how users voted based on where they live. This map would appear in a mobile iOS app, and I want it to be as visually appealing as possible (even looking like artwork) while also accurately displaying the voting data.
The location data I have planned to collect for each user at the moment is zip codes (US only), but this can definitely be changed.
I was thinking of a couple options for showing the votes:
Each zip-code region is filled with a solid color representing the net yes-votes. This would give the map starkly contrasting regions.
Same as option 1 but add a blur on top. This blur would create the illusion that the zip-codes are blended together.
Show circles of fixed radius with the color representing the net yes-votes (like in option 1) and the opacity representing how many votes there are in that region.
Show circles of fixed opacity with the color representing the net yes-votes (like in option 1) and the radius representing how many votes there are in that region.
I could not settle on any of these examples; the first I worry will look too boxy, the second hard to use, the third haphazardly done, and the fourth ugly. In truth, it is quite difficult and time consuming to implement each one, so I unfortunately do not have examples to show what each would look like in practice. That is why I am consulting the graphic design pros and enthusiasts on this site:
What is the best way to design a map that displays how a population voted? Do you favor one of these four options I proposed? Do you have any other propositions? Do you think that zip code is too small?––I was hoping to get as detailed a picture as possible, but is this too detailed?
Also, help with tags would be much appreciated.