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繪製地圖時,我可以繪製一個英國地圖ggmap
有這樣一個觀點:大型白色邊框採用ggmap
library(ggmap)
UK_map <- get_map(location = c(-2.65, 53.7), zoom = 5, maptype = "hybrid")
UK_map <- ggmap(ggmap=UK_map, extent = "device", legend = "right")
UK_map <- UK_map + geom_point(data = data.frame(x = -1.81, y = 55.655), aes(x, y), size = 5)
而且我可以用溫斯頓·張的multiplot
功能出兩個地塊在同一個窗口:
multiplot <- function(..., plotlist=NULL, cols) {
require(grid)
# Make a list from the ... arguments and plotlist
plots <- c(list(...), plotlist)
numPlots = length(plots)
# Make the panel
plotCols = cols # Number of columns of plots
plotRows = ceiling(numPlots/plotCols) # Number of rows needed, calculated from # of cols
# Set up the page
grid.newpage()
pushViewport(viewport(layout = grid.layout(plotRows, plotCols)))
vplayout <- function(x, y)
viewport(layout.pos.row = x, layout.pos.col = y)
# Make each plot, in the correct location
for (i in 1:numPlots) {
curRow = ceiling(i/plotCols)
curCol = (i-1) %% plotCols + 1
print(plots[[i]], vp = vplayout(curRow, curCol))
}
}
multiplot(UK_map, UK_map, cols = 2)
但在使用時multiplot
,大量白色邊框的上方和下方出現地圖,如附圖所示。有沒有辦法阻止這個白色邊框出現?