I repeat the question because it seems that the code did not get attached.
Dear R users,
I am struggling to understand *curveGrob* and *annotation_custom* command
in *ggplot*.
In brief my issue can be approximated to drawing a downward sloping arrow
curve
from point (5,5) to (10,0) but keep on getting (5,0) to (10,5) |=> see
attached arrows.png
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(col="blue"), 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=myCurve,5,10,5,0) + # !!!!!this should draw from
(5,5) to (10,0) but it does not*
annotation_custom(grob=myCurve2,2.5,6,2.5,10) # plot from 2.5,2.5 to 6,6
In more detail:
I am building a shiny application (like in shiny_pic.png).
after choosing country 1 and country 2, R would plot a map of Europe,
highlight the two selected countries with different colors
and draw a curved arrow from country 1 in its respective color towards
country2
and vice versa from country 2 to country 1 in the color of country 2.
size of the arrow would correspond with trade between the two countries.
since it is a shiny application I need a code that works fast.
map does not have to be beautiful, the speed of the application is a
priority.
for the curved arrows I tried geom_curve but either the arrow was not drawn
at all
or would only appear after a wait for several minutes...
I searched stackoverflow and have found a very similar problem:
http://stackoverflow.com/questions/20216179/plot-curved-lines-between-two-locations-in-ggplot2
and although it works very well for a couple of countries like Italy-Poland
(the only thing I had to change inside curveGrov2(arrow(ends="first"))
for the arrow head to appear at the beginning, not the end.
but the problem starts with country combinations like Austria-Cyprus or
France-Greece.
It seems that x-coordinates are respected, but y-coordinates inverted
to draw an *upward* looking curve.
it has been a while that I am looking at this problem so perhaps I have
lost a fresh eye.
is there some parameter I need to tweak in curveGrob function?
fyi: my map does not have to be plotted with ggplot2.
I am open to other solutions such as spplot etc.
as long as it works fast (shiny)
and draws the arrows as desired
with every country combination and code execution.
I would be grateful for any help and I am open to every feedback
if there is something I can improve in my code please fell free...
Milena
aka suzukiblue
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###
rm(list = ls())
rm(list=lsf.str())
library(rgeos)
library(stringr)
library(reshape)
library(maptools)
library(ggplot2)
library(SmarterPoland)
library(sp)
library(grid)
library(rgdal)
# choose your working directory for shapefile download
setwd("C:/Users/Milena/Documents/R")
current.dir <- getwd()
#download the shapefile
download.file("http://thematicmapping.org/downloads/TM_WORLD_BORDERS-0.3.zip",
destfile="TM_WORLD_BORDERS-0.3.zip")
#unzip to SpatialPolygonsDataFrame
unzip("TM_WORLD_BORDERS-0.3.zip")
world <- readOGR(dsn = current.dir, layer = "TM_WORLD_BORDERS-0.3")
# extract from the world shapefile only the EU countries
c.eu <- c("AUT", "BEL", "BGR", "HRV",
"CYP", "CZE", "DNK", "EST",
"FIN",
"FRA", "DEU", "GRC", "HUN",
"IRL", "ITA", "LVA", "LTU",
"LUX",
"MLT", "NLD", "POL", "PRT",
"ROU", "SVK", "SVN", "ESP",
"SWE",
"GBR")
vec.data.eu <- rep(0, times=length(c.eu))
for (i in 1:length(c.eu) )
{vec.data.eu[i] = which(world at data[, "ISO3"]==c.eu[i])}
world.eu1 <- world[vec.data.eu,]
world.eu <- world.eu1
# country centroids (middle points in each EU country)
LAT <- c(47.33, 50.83, 43.00, 45.17, 35.00, 49.75, 56.00,
59.00, 64.00, 46.00, 51.50, 39.00, 47.00, 53.00,
42.83, 57.00, 56.00, 49.75, 35.92, 52.50, 52.00,
39.50, 46.00, 48.67, 46.25, 40.00, 62.00, 54.00)
LONG <- c(13.33, 4.00, 25.00, 15.50, 33.00, 15.00, 10.00,
26.00, 26.00, 2.00, 10.50, 22.00, 20.00, -8.00,
12.83, 25.00, 24.00, 6.17, 14.43, 5.75, 20.00,
-8.00, 25.00, 19.50, 15.17, -4.00, 15.00, -4.00)
cent <- cbind(LAT,LONG)
rownames(cent) <- c.eu
# choose two countries and display them in two different colors (color A and
color B)
# I create a vector of ones length equal to the number of countries (28)
world.eu <- world.eu1
a <- rep(1, length(c.eu))
# and overwrite the value for the 1st selected country with value 2
# and the 2nd selected country with 3
cor1 <<- 15 #Italy
cor2 <<- 21 #Poland
a[cor1] <- 2
a[cor2] <- 3
# combine the vector of levels with country names
# and call the factor column "score"
b <- cbind(c.eu, a)
dataframe2 <- data.frame(b)
colnames(dataframe2) <-c("Country.Code", "score")
# merge score with the spatial points data frame
# and pass it to ggplot for visualization
matched.indices.eu <- match(world.eu at data[, "ISO3"],
dataframe2[, "Country.Code"])
world.eu at data <- data.frame(world.eu at data,
dataframe2[matched.indices.eu, ])
world.f.eu <- fortify(world.eu, region = "ISO3")
world.m.eu <- merge(world.f.eu, world.eu at data, by.x = "id", by.y
= "Country.Code")
# draw curved arrows from country A to country B in color A (an arrow head
pointing at country B)
# and from country B to country A in color B (an arrow head pointing at country
A)
# the size of the arrow should correspond with the size of trade flow
# from country A to B and from B to A
# (that is however not the object of that question and could be done later)
# since the ggplot will be encapsulated in a shiny application
# code should draw correct arrows in every country A and country B combination
# and should execute really fast.
# I made a trial with geom_curve but the arrows either did not appear at all
# (even though no error message was displayed)
# or if appear that would be after a long wait
# I found function curveGrob (which worked quite fast on my machine)
# and annotation_custom to pass it to ggplot
# I thought that it would be a solution.
# my problem is similar I also want to visualize export between countries
# all I had to change was the curvature of the first arrow to the -0.3
# and assign the arrow head of to the beginning not the end of the arrow
myCurve<-curveGrob(0, 0, 1, 1, default.units = "npc",
curvature = -0.3, angle = 60, ncp = 20, shape = 1,
square = FALSE, squareShape = 1,
inflect = FALSE, arrow = arrow(length = unit(0.15,
"inches"), type="closed"), open = TRUE,
debug = FALSE,
name = NULL, gp = gpar(col="blue", lwd=10,
lineend="round", fill="blue"), vp = NULL)
myCurve2<-curveGrob(0, 0, 1, 1, default.units = "npc",
curvature = 0.3, angle = 60, ncp = 20, shape = 1,
square = FALSE, squareShape = 1,
inflect = FALSE, arrow = arrow(length = unit(0.15,
"inches"), type="closed", ends="first"),
open = TRUE, debug = FALSE,
name = NULL, gp = gpar(col="magenta", lwd=2,
lineend="round", fill="magenta"), vp = NULL)
ggplot(world.m.eu, aes(long, lat, group = group))+
geom_polygon(aes(fill = world.m.eu$score),show.legend=FALSE)+
geom_polygon(data = world.m.eu, aes(long,lat),
fill="NA", color = "white", size=0.01) +
coord_cartesian(xlim = c(-17, 37), ylim = c(34, 72))+
scale_fill_manual(values = c("lightblue", "blue",
"magenta")) +
annotation_custom(grob=myCurve, xmin=cent[cor1,2], xmax=cent[cor2,2],
ymin=cent[cor1,1], ymax=cent[cor2,1]) +
annotation_custom(grob=myCurve2,xmin=cent[cor2,2], xmax=cent[cor1,2],
ymin=cent[cor2,1], ymax=cent[cor1,1])
# however what worked for the combination Italy - Poland
# and perhaps a few others
# does not work for example for Austria - Cyprus
# or France - Greece.
# it seems that regardless the assignment of xmin and xmax
# or ymin and ymax
# it looks like the ys are switched
# for the lines to be drawed upwards
### Austria - Cyprus
world.eu <- world.eu1
a <- rep(1, length(c.eu))
cor1 <<- 1 #Austria
cor2 <<- 5 #Cyprus
a[cor1] <- 2
a[cor2] <- 3
b <- cbind(c.eu, a)
dataframe2 <- data.frame(b)
colnames(dataframe2) <-c("Country.Code", "score")
matched.indices.eu <- match(world.eu at data[, "ISO3"],
dataframe2[, "Country.Code"])
world.eu at data <- data.frame(world.eu at data,
dataframe2[matched.indices.eu, ])
world.f.eu <- fortify(world.eu, region = "ISO3")
world.m.eu <- merge(world.f.eu, world.eu at data, by.x = "id", by.y
= "Country.Code")
myCurve<-curveGrob(0, 0, 1, 1, default.units = "npc",
curvature = -0.3, angle = 60, ncp = 20, shape = 1,
square = FALSE, squareShape = 1,
inflect = FALSE, arrow = arrow(length = unit(0.15,
"inches"), type="closed"), open = TRUE,
debug = FALSE,
name = NULL, gp = gpar(col="blue", lwd=10,
lineend="round", fill="blue"), vp = NULL)
myCurve2<-curveGrob(0, 0, 1, 1, default.units = "npc",
curvature = 0.3, angle = 60, ncp = 20, shape = 1,
square = FALSE, squareShape = 1,
inflect = FALSE, arrow = arrow(length = unit(0.15,
"inches"), type="closed", ends="first"),
open = TRUE, debug = FALSE,
name = NULL, gp = gpar(col="magenta", lwd=2,
lineend="round", fill="magenta"), vp = NULL)
ggplot(world.m.eu, aes(long, lat, group = group))+
geom_polygon(aes(fill = world.m.eu$score),show.legend=FALSE)+
geom_polygon(data = world.m.eu, aes(long,lat),
fill="NA", color = "white", size=0.01) +
coord_cartesian(xlim = c(-17, 37), ylim = c(34, 72))+
scale_fill_manual(values = c("lightblue", "blue",
"magenta")) +
annotation_custom(grob=myCurve, xmin=cent[cor1,2], xmax=cent[cor2,2],
ymin=cent[cor1,1], ymax=cent[cor2,1]) +
annotation_custom(grob=myCurve2,xmin=cent[cor2,2], xmax=cent[cor1,2],
ymin=cent[cor2,1], ymax=cent[cor1,1])
### France - Greece
world.eu <- world.eu1
a <- rep(1, length(c.eu))
cor1 <<-10 #France
cor2 <<-12 #Greece
a[cor1] <- 2
a[cor2] <- 3
b <- cbind(c.eu, a)
dataframe2 <- data.frame(b)
colnames(dataframe2) <-c("Country.Code", "score")
matched.indices.eu <- match(world.eu at data[, "ISO3"],
dataframe2[, "Country.Code"])
world.eu at data <- data.frame(world.eu at data,
dataframe2[matched.indices.eu, ])
world.f.eu <- fortify(world.eu, region = "ISO3")
world.m.eu <- merge(world.f.eu, world.eu at data, by.x = "id", by.y
= "Country.Code")
myCurve<-curveGrob(0, 0, 1, 1, default.units = "npc",
curvature = -0.3, angle = 60, ncp = 20, shape = 1,
square = FALSE, squareShape = 1,
inflect = FALSE, arrow = arrow(length = unit(0.15,
"inches"), type="closed"), open = TRUE,
debug = FALSE,
name = NULL, gp = gpar(col="blue", lwd=10,
lineend="round", fill="blue"), vp = NULL)
myCurve2<-curveGrob(0, 0, 1, 1, default.units = "npc",
curvature = 0.3, angle = 60, ncp = 20, shape = 1,
square = FALSE, squareShape = 1,
inflect = FALSE, arrow = arrow(length = unit(0.15,
"inches"), type="closed", ends="first"),
open = TRUE, debug = FALSE,
name = NULL, gp = gpar(col="magenta", lwd=2,
lineend="round", fill="magenta"), vp = NULL)
ggplot(world.m.eu, aes(long, lat, group = group))+
geom_polygon(aes(fill = world.m.eu$score),show.legend=FALSE)+
geom_polygon(data = world.m.eu, aes(long,lat),
fill="NA", color = "white", size=0.01) +
coord_cartesian(xlim = c(-17, 37), ylim = c(34, 72))+
scale_fill_manual(values = c("lightblue", "blue",
"magenta")) +
annotation_custom(grob=myCurve, xmin=cent[cor1,2], xmax=cent[cor2,2],
ymin=cent[cor1,1], ymax=cent[cor2,1]) +
annotation_custom(grob=myCurve2,xmin=cent[cor2,2], xmax=cent[cor1,2],
ymin=cent[cor2,1], ymax=cent[cor1,1])
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