绘制ggplot2中两个位置之间的曲线 [英] Plot curved lines between two locations in ggplot2

问题描述

我正在制作一张关于从美洲出口到荷兰的地图。为了使我的数据可视化，我想用美洲国家到荷兰的箭头制作地图。我使用cshapes世界地图和ggplot2。

  data = data.frame（Country.name= c（Brazil，USA，Canada， 巴拉圭，乌拉圭），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）
区域。 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 *（52.13-1ng））），
箭头=箭头（长度=单位（0.5，厘米），角度= 45，类型=关闭））
  

我发现直线绘制时线条重叠。这很丑陋。因此，我正在寻找一种在ggplot2中的坐标之间绘制曲线的方式，因此它们不会重叠。 / div>

由于某些原因，我无法运行 cshapes ，但这里有一个如何使用 curveGrob（） code> grid 包和 ggplot2 的 annotation_custom（） code>函数。它给你很大的灵活性。 PS：大部分参数只是默认值。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， （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至10,10 
 annotation_custom（grob = myCurve2,2.5,6,2.5,6）＃plot from 2.5,2.5 to 6,6 
 
＃REFERENCE&g t;>> http：//stat.ethz.ch/R-manual/R-devel/library/grid/html/grid.curve.html 
  

I am making a map about exports from the Americas to the Netherlands. To visualise my data, I want to make a map with arrows from countries in the Americas to the Netherlands. I use a cshapes world map and 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"))

I have found that the lines overlap when they are plotted straight. This is ugly. Therefore, I am looking for a way to plot curved lines between coordinates within ggplot2, so they don't overlap.

解决方案

I couldn't run cshapes for some reason, but here's an example of how to build curves using curveGrob() from the grid package and ggplot2's annotation_custom() function. It gives you a lot of flexibility. PS: most of the params are just defaults. Edit - updated to show 2 curves.

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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