Interactive Plotly

The idea is about using package plotly for producing interactive plots for a Shiny application.
Official documentation about plotly is superb. Nevertheless, as this graphics grammar, within the R community is not as spread as ggplot is, few topics require a bit of extra research.

Intro

Given

• a data set with four columns: x, y , w, z
• a plot x and y onto pl1
• plot w and z onto pl2
• pl as a subplot of pl1 and pl2

I would like to:

• be able to select a set of adiacent points in pl1
• observe the selected points marked with new color and larger size
• observe the same effect on corresponding points on pl2

I will be using the classic iris data for this example.

Step 1:

Load the required packages

require(plotly)
require(dplyr)

Step 2:

Add a unique id to data

data <- iris %>% mutate ( id = 1:n())

Step 3:

Transform data into a ShareData object

data <- data %>% highlight_key(~id) 

Step 4:

Build your plots as you would normally do

pl1 <- plot_ly(data, 
               x = ~ Sepal.Length, y = ~Sepal.Width, 
               type = 'scatter', mode = 'markers', 
               marker = list ( color = 'green')) %>% 
  layout(showlegend=F)
               
pl2 <- plot_ly(data, 
               x = ~Petal.Length, y = ~Petal.Width, 
               type = 'scatter', mode = 'markers',
               marker = list ( color = 'blue')) %>% 
  layout(showlegend=F)

Step 5:

Bind your plots into a single subplot

pl <- subplot(pl1, pl2, nrows = 2)

Step 6:

Link the plots

pl <- pl %>% 
  highlight(on = "plotly_select", off = 'plotly_doubleclick', 
            opacityDim = .5, 
            selected = attrs_selected(marker = list ( size = 20, color = 'orange')))

Step 7:

Display results

pl