r - when knit rmd the html file does not show interactive leaflet maps

Question

I'm trying to plot spatial data on interactive maps using "mapview" and "purrr". The maps are visible when using Rstudio in the .rmd but not when knitting the html. This way of presenting data in rmd is supported by "ggplot2", so I thought exporting maps in html would be useful.

Sample data:

library(mapview)
library(dplyr)
library(purrr)

df <- data.frame(lon = 1:9,
                 lat = 1:9,
                 id = c(rep(1,5), rep(2,4))) %>% 
      st_as_sf(coords = c("lon", "lat"), crs = 4326)

# split dataframe in multiple datasets (to produce multiple plots for each group of data)
df <- split(df, df$id)

When trying to plot in html with "purrr" and "mapview":

df %>% map(mapview)

The output in html:

The output in Rstudio (both maps are available):

have u tried with plot_ly ...most of the time it works easily with `plotly` — sai saran, Nov 09 '18 at 13:31
i am not that much stronger in map view using ggplot...can u try to plot the same map view using ggplot or plotly function then u will get — sai saran, Nov 09 '18 at 13:41
plotting maps with ggplot would require loading ggmap which requires api key. Trying to avoid that — adl, Nov 09 '18 at 14:25

score 2 · Accepted Answer · answered Nov 14 '18 at 09:51

You can use htmltools::tagList(), see: How to render leaflet-maps in loops in RMDs with knitr

If you want to use the tidyverse:

---
title: "R Notebook"
output:
  html_document
---


```{r}
library('tidyverse')
library('sf')
library('mapview')
library('htmltools')

# create data set
df = data.frame(lon = 1:9,
                 lat = 1:9,
                 id = c(rep(1,5), rep(2,4))) %>% 
      st_as_sf(coords = c("lon", "lat"), crs = 4326)

# split dataframe in multiple datasets (to produce multiple plots for each group of data)
df = split(df, df$id)



# create maps
df_maps = df %>% 
  purrr::set_names() %>% 
  map(.x = .,
      .f = mapview) %>% 
  map(.x = ., slot, name = "map")

# add html headers
df_maps =
  imap(.x = df_maps,
       .f = function(x, y) {
        list(h4(paste("Subset:", y)),
             x)
      }) %>%
  flatten()

# for printing the maps
tagList(df_maps)
```

When I run this only the first geometry plots in the rmarkdown output. The second plots extent is set to the 2nd geometry set but only the first set of points is plotted. Anyone have an idea how to fix this issue (same code as this answer)? — Chris, May 06 '22 at 00:00

r - when knit rmd the html file does not show interactive leaflet maps

1 Answers1