2

Willing to plot multiple barplots on a map, I was able to use this solution below, converting ggplots into images with r magick and putting them on map - also an image.

Any way to plot multiple barplots on a map?

I want to create multiple maps each time, having 10 scenarios, with each 12 barplots to put on the map. I tried implementing a loop, but the image_graph function from magick doesn't work within.

library(ggmap)
library(maps)
library(ggplot2)
library(magick)

mp <-  NULL
mapWorld <- borders("world", colour="gray70", fill="gray70") 

fig <- image_graph(width = 850, height = 550, res = 96)
ggplot() + mapWorld
dev.off()


 df <- data.frame(region = c('France','UK'), name =
 c('A','B','C','A','B','C'), value1 = c(20,15,15,10,8,8), value2 =
 c(10,15,20,5,8,10) , value3 = c(5,15,10,3,8,5) )

 scenarios = c('value1', 'value2', 'value3')

    for (scenario in scenarios ) {

              for (reg in unique(df$region) ) {

                df_reg = df[ (df$region == reg), ]


                bp <- ggplot(df_reg, aes_string(x = "region", y = scenario, fill = "name")) +
                  geom_bar(stat = 'identity') +
                  theme_bw() + 
                  theme(legend.position = "none", axis.title.x = element_blank(), axis.title.y = element_blank())


                barfig <- image_graph(width = 100, height = 75, res = 72)
                bp
                dev.off()

                barplotname = paste0('barfig_',reg )

                assign(barplotname, barfig)

              }


    final <- image_composite(fig, barfig_France, offset = "+75+150")
    final <- image_composite(final, barfig_UK, offset = "+325+125")
    final

    filename = paste0('map_', scenario , ".png")
    image_write(final, path = filename, format = "png" )

    }

It works properly if I decompose the loop manually as below, and I can't find why it doesn't in the loop. I didn't find info in the magick documentation or examples of uses of the image_graph function within loops. 

              for (reg in unique(df$region) ) {

                df_reg = df[ (df$region == reg), ]


                bp <- ggplot(df_reg, aes_string(x = "region", y = "value1")) + geom_bar(stat = 'identity', aes(fill = name) ) +  #trying in one 
                  theme_bw() + 
                  theme(legend.position = "none", axis.title.x = element_blank(), axis.title.y = element_blank())

                barplotname = paste0('bp_',reg )

                assign(barplotname, bp)

              }

      barfig_France <- image_graph(width = 100, height = 75, res = 72)
      bp_France
      dev.off()

      barfig_UK <- image_graph(width = 100, height = 75, res = 72)
      bp_UK
      dev.off()


    final <- image_composite(fig, barfig_France, offset = "+75+150")
    final <- image_composite(final, barfig_UK, offset = "+325+125")
    final

If I try to integrate this block in the "for (scenarios... )" loop, issue remains the same, I fail to convert my plots into images

user213544
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TotoBB
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2 Answers2

1

Found a basic workaround consisting in saving barplots then importing them again using image_read

for (scenario in scenarios ) {

          for (reg in unique(df$region) ) {

            df_reg = df[ (df$region == reg), ]

            bp <- ggplot(df_reg, aes_string(x = "region", y = scenario)) + geom_bar(stat = 'identity', aes(fill = name) ) +  #trying in one 
            theme_bw() + 
            theme(legend.position = "none", axis.title.x = element_blank(), axis.title.y = element_blank())

            barplotname = paste0('barfig_',reg, '.svg')

            ggsave(barplotname, bp, width = 1.2, height = 1, dpi = 72)


            plotname = paste0('barfig_', reg)
            img = image_read_svg(barplotname)
            assign(plotname ,img)

          }

    final <- image_composite(fig, barfig_France, offset = "+75+150")
    final <- image_composite(final, barfig_UK, offset = "+325+125")
    final

    filename = paste0('map_', scenario , ".png")
    image_write(final, path = filename, format = "png" )

}
TotoBB
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0

I think you need to print() the ggplot object inside the loop rather than just calling it, i.e.

barfig <- image_graph(width = 100, height = 75, res = 72)
print(bp) # not bp
dev.off()
PhilMo
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