Generating radar plots using single dataframe

Question

I have a dataframe dat which I use to generate radar plots of different weather conditions (columns) in different sites (denoted by each row arc1045, arc1047 ...) The first two rows of the dataframe are added to indicate the maximum and minimum values of each climatic condition following the example here

        ambient_air_temperature relative_humidy barometric_pressure average_wind_speed particulate_density_2.5 particulate_density_10
1                     85.000000        100.0000            2000.000         160.000000              999.900000             1999.90000
2                    -40.000000          0.0000              10.000           0.000000                0.000000                0.00000
arc1045                9.176667         71.0700            1013.167           4.043333                5.133333               25.16667
arc1047                8.492500         80.9600            1014.000           2.035000                5.600000               25.10000
arc1048                8.477500         76.9875            1012.675           6.842500                6.275000               28.15000
arc1050                8.475000         76.5525            1013.775           6.335000                5.175000               30.20000

I then follow the approach described here to generate URIs of the plots to be included as markers on a leaflet map

library(fmsb)

    makePlotURI <- function(expr, width, height, ...) {
      pngFile <- plotPNG(function() { expr }, width = width, height = height, ...)
      on.exit(unlink(pngFile))
      base64 <- httpuv::rawToBase64(readBin(pngFile, raw(1), file.size(pngFile)))
      paste0("data:image/png;base64,", base64)
    }

rep(makePlotURI(radarchart(dat), 300, 300, bg = "transparent"), 4)

However, here each radar plot contains multiple polygons, with each polygon representing a site. I want each radar plot to have a single polygon and visualize the weather conditions on a single site.

Answer 1

It is fairly straightforward to do this, instead of passing the whole data frame to radachart() function, just pass the required data for one site.

df = data.frame(ambient_air_temp = c(85, -40, 9.176667, 8.492500,  8.477500, 8.475000),
                rel_hum = c(100.0000,0.0000,71.0700, 80.9600, 76.9875,76.5525 ),
                bar_pre = c(2000.000, 10.000, 1013.167, 1014.000, 1012.675, 1013.775),
                ave_ws = c(160,0,4.043333,2.035000,6.842500,6.335000),
                pd2.5 = c(999.9, 0, 5.133333, 5.600000, 6.275000, 5.175000),
                pd10 = c(1999.9, 0, 25.16667, 25.10000, 28.15000, 30.20000))

row.names(df) = c("1","2","arc1045","arc1047","arc1048","arc1050")

library(fmsb)
pltrd = function(idx) radarchart(df[c(1,2,idx),], title = row.names(df)[idx])

Since your data is in rows = {3,4,5,6}, you can call this function using those row values. Note that rows = {1, 2} are required to be the minimum/maximum values for each variable...

pltrd(3)

pltrd(4)

pltrd(5)