In during the presidential primaries of 2008, I kept up with results a mapped them at the county level for both Democrats and Republicans. Because of my more intimate involvement, the more interesting dynamic, and the longer effective duration of the Democratic race, those maps are more complete than the Republican primary maps.
Because of the more uniform procedures across state lines in the Democratic contest, there is also a clearer trend in voting patterns that is visible across state lines despite the variability of contest dates.
Meng Bomin 