我正在绘制一张有关从美洲到荷兰的出口的地图。为了使我的数据可视化,我想用箭头绘制一个从美洲国家到荷兰的地图。我使用cshapes世界地图和ggplot2。
data = data.frame("Country.name" = c("Brazil","USA","Canada","Paraguay","Uruguay"), "lng" =
c(14.23,37,56.13,-23.44,-32.52), "lat" = c(-51.92,-95.71,-106.34,-58.44,-55.77))
require(cshapes)
cshp.data = cshp(date=as.Date("2012-1-1"), useGW=TRUE)
region.data.frame = fortify(cshp.data, region = "ISO1AL3")
ggplot(region.data.frame) + geom_polygon(aes(long,lat,group=group)) +
geom_segment(data = data, aes(x = lat, y = lng, xend= (5.29 - 0.1 * (5.29 - lat)), yend= (52.13 - 0.1 * (52.13 - lng))),
arrow=arrow(length=unit(0.5,"cm"), angle = 45, type = "closed"))
我发现直线绘制时这些线重叠。这很丑。因此,我正在寻找一种在ggplot2中的坐标之间绘制曲线的方法,以使它们不重叠。
我不能运行cshapes
出于某种原因,但这里有一个如何建立使用曲线的例子curveGrob()
从grid
包和ggplot2
的annotation_custom()
功能。它给您很大的灵活性。PS:大多数参数只是默认值。编辑-更新为显示2条曲线。
require(grid)
g<-qplot(c(0,10),c(0,10))
myCurve<-curveGrob(0, 0, 1, 1, default.units = "npc",
curvature = 0.3, angle = 90, ncp = 20, shape = 1,
square = FALSE, squareShape = 1,
inflect = FALSE, arrow = arrow(), open = TRUE,
debug = FALSE,
name = NULL, gp = gpar(), vp = NULL)
myCurve2<-curveGrob(0, 0, 1, 1, default.units = "npc",
curvature = -0.3, angle = 60, ncp = 10, shape = 1,
square = FALSE, squareShape = 1,
inflect = FALSE, arrow = arrow(), open = TRUE,
debug = FALSE,
name = NULL, gp = gpar(), vp = NULL)
g +
annotation_custom(grob=myCurve,0,10,0,10) + # plot from 0,0 to 10,10
annotation_custom(grob=myCurve2,2.5,6,2.5,6) # plot from 2.5,2.5 to 6,6
#REFERENCE>>http://stat.ethz.ch/R-manual/R-devel/library/grid/html/grid.curve.html
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