Polygons nicely cropping ggplot2/ggmap at different zoom levels

Question

I am playing with a spatial data set (mostly polygons over an area of a city) and I would like to produce different views, based on different levels of zoom. Everything is f

Answer 1

Generally, this clipping is due to zooming using the scale limits (which drop points outside the range) versus using the coord limits (which is a true zoom, just drawing the parts inside with the parts outside the range still there). ggmap does not have a straightforward way to indicate the second type of zoom should be used, but looking at the function, the relevant parts can be pulled out and put back together:

s12 <- get_map(maptype = "satellite", zoom = 12) 
ggmap(s12, base_layer=ggplot(aes(x=lon,y=lat), data=zips),
      extent = "normal", maprange=FALSE) +
    geom_polygon(aes(x = lon, y = lat, group = plotOrder),
                 data = zips, colour = NA, fill = "red", alpha = .5) +
    geom_path(aes(x = lon, y = lat, group = plotOrder),
              data = zips, colour = "white", alpha = .7, size = .4) +
    coord_map(projection="mercator", 
              xlim=c(attr(s12, "bb")$ll.lon, attr(s12, "bb")$ur.lon),
              ylim=c(attr(s12, "bb")$ll.lat, attr(s12, "bb")$ur.lat)) +
    theme_nothing()