Colour shapefile using multiple attributes

Question

library(raster)
admin <- getData('GADM', country='FRA', level=2)

set.seed(123)

id <- data.frame(ID_2 = admin@data$ID_2, day1 = sample(1:20,96,replace = T), 
                                   day2 = sample(50:80,96,replace = T), 
                                   day3 = sample(120:140,96,replace = T), 
                                   day4 = sample(200:230,96,replace = T))

 admin.shp <- merge(admin,id)

If I want to colour the plot using either day1, day2, day3 or day4, I can do this:

plot(admin.shp, col = admin.shp@data$day1)

What I am trying to do is to produce some sort of .gif file or animation that goes from day 1 to day 230:

  range <- c(min(id$day1),max(id$day4))

If the day matches values in day1, the polygon should turn green, If it matches in day2 that polygon should turn blue, If it matches in day3 that polygon should turn orange, If it matches in day4 that polygon should turn red

If I had to do this for a single column (for e.g. day1), I can do this:

library(magick)
c(min(id$day1),max(id$day1)) # 1, 20  

for(i in 1:20){

   breaks.pl <- c(0, i, 21) 
   col.pl <- c("green4","white")
   cuts.pl <- cut(data.frame(admin.shp)[, "day1"],breaks = breaks.pl)

   png(paste0(i,".png"), width = 1000, height = 600)
   plot(admin.shp, col = col.pl[cuts.pl], border = 'transparent', main = paste0("day:",i))
   plot(admin.shp, add = T)
   dev.off()
 }

This will produce a series of png files and I can then generate a .gif of these 20 png files to create an animation for day1

list.png <- list()

for(i in 1:20){
png.file <- image_read(path = paste0(i,".png"))
list.png[[i]] <- png.file
}

png.stack1 <- list.png[[1]]

for(i in 1:20){
    png.stack <- list.png[[i]]
    png.stack1 <- c(png.stack1,png.stack)
 } 

 png.img <- image_scale(png.stack1)
 png.ani <- image_animate(png.img, fps = 1, dispose = "previous")

 image_write(png.ani, "my.animation.gif")

However, I want to extent this so that I use all the four columns day1 to day4

could you melt the `id` data.frame to give you just the one column: `library(reshape2); id <- melt(id, id.vars = "ID_2")` ? — SymbolixAU, Apr 14 '18 at 12:27
I can melt the column. But then how do I create the animation? — 89_Simple, Apr 14 '18 at 13:49

DJack · Accepted Answer · 2018-04-14T15:10:30.907

2

Adapted from your code, this should do the trick:

colors = c("white", "green4", "blue", "orange", "red")

library(animation)
ani.options(interval=.05)

i = 0
saveGIF({
  for(k in 2:5){
    while (i < max(id[,k])) {
      print(i)
      i = i + 1 
      breaks.pl <- c(0, i, max(id$day4)+1) 
      col.pl <- c(colors[k], colors[k-1])
      cuts.pl <- cut(data.frame(id)[, k], breaks = breaks.pl)

      plot(admin.shp, col = col.pl[cuts.pl], main = paste0("day:",i))
    } 
  } 
})

Demo:

edited Apr 14 '18 at 15:10

answered Apr 14 '18 at 13:31

DJack

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Just a quick check: did you made the .gif using the same way I did? – 89_Simple Apr 14 '18 at 13:47
No. I used an online tool (for convenience). – DJack Apr 14 '18 at 13:49
If possible, could you point me to the online tool if its available for free. That will make my life easier. – 89_Simple Apr 14 '18 at 14:00
I have used this http://gifmaker.me/ (randomly chosen from google results) but I think it is limited to 200 images. It's why my demo is not complete. These kind of tools are very popular, you should be able to find another one without this limitation. – DJack Apr 14 '18 at 14:04
The easiest solution would be to use the `animation` package. See here for an example: http://www.programmingr.com/content/animations-r/. – DJack Apr 14 '18 at 14:46

Colour shapefile using multiple attributes

1 Answers1