The precincts in my county change every year. I want to classify voting patterns over 8 years. It would be helpful if there was a common shape I could use to compare the precincts over several years. Voting districts (precincts) are comprised at a smaller scale of Census blocks and consistently roll up into legislative districts. Census tracts or Census blocks don't align. Is there a GIS tool about which I should be learning? Suggestions would be appreciated and if there is a group on Geonet exploring voting I would appreciate collaboration.