R: Are "Counts" Necessary for Interactive Plotly Titles? - r

Question

I am working with the R Programming language.
Using the following link as a tutorial (https://plotly.com/r/lines-on-maps/), I was able to make an interactive plot:
#load libraries
library(dplyr)
library(leaflet)
library(plotly)
library(data.table)
#generate data for example (longitude and latitude of cities)
lat = rnorm(100, 43, 3)
long = rnorm(100, -79, 3)
map_data = data.frame(lat, long)
map_data$type = as.factor(1:100)
#change format of the data so that it is compatible for this example
result = rbind(
cbind(map_data[1:nrow(map_data)-1,c(1,2)], map_data[-1,c(1,2)]),
cbind(map_data[nrow(map_data), c(1,2)], map_data[1,c(1,2)])
)
colnames(result) <- c("start_lat", "start_long", "end_lat", "end_long")
my_data = result
my_data$type = as.factor(1:nrow(my_data))
my_data$type1 = as.character(1:100)
my_data$count = as.integer(1)
my_data$id = 1:100
#### begin visualization
# map projection
geo <- list(
scope = 'north america',
projection = list(type = 'azimuthal equal area'),
showland = TRUE,
landcolor = toRGB("gray95"),
countrycolor = toRGB("gray80")
)
fig <- plot_geo(locationmode = 'USA-states', color = I("red"))
fig <- fig %>% add_markers(
data = my_data, x = ~start_long, y = ~start_lat, alpha = 0.5
)
fig <- fig %>% add_markers(
data = my_data, x = ~start_long, y = ~start_lat, hoverinfo = "text", alpha = 0.5
)
fig <- fig %>% add_segments(
data = group_by(my_data, type),
x = ~start_long, xend = ~end_long,
y = ~start_lat, yend = ~end_lat,
alpha = 0.3, size = I(1), hoverinfo = "none"
)
fig <- fig %>% layout(
title = 'Plot 1',
geo = geo, showlegend = FALSE, height=800
)
#final result
fig
This produces the following result:
Now, I am trying to get the "interactive text" to work:
# map projection
geo <- list(
scope = 'north america',
projection = list(type = 'azimuthal equal area'),
showland = TRUE,
landcolor = toRGB("gray95"),
countrycolor = toRGB("gray80")
)
fig <- plot_geo(locationmode = 'USA-states', color = I("red"))
fig <- fig %>% add_markers(
data = my_data, x = ~start_long, y = ~start_lat, alpha = 0.5
)
fig <- fig %>% add_markers(
data = my_data, x = ~start_long, y = ~start_lat, text = ~type1, size = ~count, hoverinfo = "text", alpha = 0.5
)
fig <- fig %>% add_segments(
data = group_by(my_data, type),
x = ~start_long, xend = ~end_long,
y = ~start_lat, yend = ~end_lat,
alpha = 0.3, size = I(1), hoverinfo = "none"
)
fig <- fig %>% layout(
title = 'Plot 1',
geo = geo, showlegend = FALSE, height=800
)
fig
The interactive text is now working, but the data points are appearing "much bulkier".
My Question: Is it possible to make the interactive text work, but have the data points appear the same way they do in the first picture?
I originally tried to do this without a "count" variable:
fig <- fig %>% add_markers(
data = my_data, x = ~start_long, y = ~start_lat, text = ~type1, hoverinfo = "text", alpha = 0.5
)
But when I do this, the interactive text isn't working - the interactive text only works when a "count" variable is added.
Is this "count" variable necessary? Can someone please show me how to fix this?
Thanks!

Answer 1

You don't need to use count. However, there is something odd here with the segments. Either way, this achieves what I think you're looking for.
I have provided two examples because you didn't say what you wanted to have in the hover text. In the first example, I just use the x and y (lat and long). In the second, I used custom hover content.
Everything that precedes the creation of fig was left unchanged.
Notable changes:
the order the fig elements are assembled; segments seems to only work if it is before the markers
hoverinfo for the segments add is now set to text--this didn't add hover content, but for some reason none here was a problem...odd
I dropped a call to fig or two, that seemed to be doing nothing...
in add_markers, this changed differently in the two options
in one, hovertext = "text" was changed to hovertext = "lat+lon"
in the other, there were multiple changes--you'll have to look at the code for this one
in layout, I deleted the height argument; it's ignored
fig <- plot_geo(locationmode = 'USA-states', color = I("red"))
fig <- fig %>% add_segments( # add segments
data = group_by(my_data, type),
x = ~start_long, xend = ~end_long,
y = ~start_lat, yend = ~end_lat,
alpha = 0.3, size = I(1), hoverinfo = "text" # changed hoverinfo
)
fig <- fig %>% add_markers(
data = my_data, x = ~start_long, y = ~start_lat,
alpha = 0.5, hoverinfo = "lat+lon" # changed hoverinfo
)
fig <- fig %>% layout(
title = 'Plot 1',
geo = geo, showlegend = FALSE # removed height argument
)
#final result
fig
Here's the custom text version
fig <- plot_geo(locationmode = 'USA-states', color = I("red"))
fig <- fig %>% add_segments( # add segments
data = group_by(my_data, type),
x = ~start_long, xend = ~end_long,
y = ~start_lat, yend = ~end_lat,
alpha = 0.3, size = I(1), hoverinfo = "text" # changed hoverinfo
)
fig <- fig %>% add_markers(
data = my_data, x = ~start_long, y = ~start_lat,
alpha = 0.5, hoverinfo = "text", # hoverinfo unchanged
text = ~paste0("Longitude: ", # text changed here**
round(my_data$start_long, 2),
"<br>Latitude: ",
round(my_data$start_lat, 2))
)
fig <- fig %>% layout(
title = 'Plot 1',
geo = geo, showlegend = FALSE # removed height argument
)
#final result
fig
Let me know if you have any questions!