zip   state  users  longitude latitude
00501  NY    1000   -72.63708 40.92233
00544  NY    1000   -72.63708 40.92233
00601  PR    2000   -66.74947 18.1801
00602  PR    2000   -67.18024 18.36329

map<-get_map(location='united states', zoom=4, maptype = "terrain",
         source='google',color='color')
ggmap(map) + geom_point(
aes(x=longitude, y=latitude, show_guide = TRUE, colour=users),
data=data, alpha=.5, na.rm = T)  +
scale_color_gradient(low="red", high="green")

map<-get_map(location='united states', zoom=4, maptype = "terrain",
         source='google',color='color')
ggmap(map) + geom_point(
aes(x=longitude, y=latitude, show_guide = TRUE, colour=users),
data=data, alpha=.5, na.rm = T)  +
scale_color_gradient(low="red", high="green")  +
geom_text(aes(x = longitude, y = latitude, label = as.character(state)),
data = data,inherit.aes = FALSE)