Leaflet (R) addPopups: coordinates/properties - r

Question

I'm fairly new to handling spatial data and leaflet in general. I'm having difficulty creating a popup for my map. Basically what I want in the popup is the coordinates of my polygon and one of the properties (the type of class). Below is an test example of my geoJSON file:
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"properties": {"class": "blah"},
"geometry": {
"type": "Polygon",
"coordinates": [
[
[
-81.7987060546875,
32.74570253945518
],
[
-81.6229248046875,
32.16631295696736
],
[
-80.958251953125,
32.4263401615464
],
[
-81.2713623046875,
32.791892438123696
],
[
-81.7437744140625,
32.97180377635759
],
[
-81.7987060546875,
32.74570253945518
]
]
]
}
},
{
"type": "Feature",
"properties": {"class": "blah2"},
"geometry": {
"type": "Polygon",
"coordinates": [
[
[
-82.056884765625,
33.55512901742288
],
[
-81.4471435546875,
33.247875947924385
],
[
-81.40869140625,
33.80653802509606
],
[
-82.078857421875,
33.88865750124075
],
[
-82.40295410156249,
33.58716733904656
],
[
-82.056884765625,
33.55512901742288
]
]
]
}
},
{
"type": "Feature",
"properties": {"class": "blahh3"},
"geometry": {
"type": "Polygon",
"coordinates": [
[
[
-83.485107421875,
32.930318199070534
],
[
-83.07861328125,
31.863562548378965
],
[
-82.21618652343749,
32.11049589629439
],
[
-82.97973632812499,
33.22030778968541
],
[
-83.726806640625,
33.211116472416855
],
[
-83.485107421875,
32.930318199070534
]
]
]
}
}
]
}
Here is the code I have so far to create my map, but I'm struggling/don't even know where to start on creating a popup that includes my coordinates and property:
blahTest <- geojson_read("/file/path/...", what = "sp")
fpal <- colorFactor("viridis", blahTest$class)
leaflet(blahTest) %>%
addTiles() %>%
addPolygons(stroke = FALSE, smoothFactor = 0.3, fillOpacity = 1,
color = ~fpal(class)) %>%
addLegend(colors = ~fpal, opacity = 1.0, labels = ~fpal) %>%
addPopups()
Thanks in advance!

Answer 1

Overview
Using #patL's suggestion, I used the popup parameter within leaflet::addPolygon() function to add label both the class and coordinates that define each polygon within blahTest.
I saved your sample data as .gejson file and imported it using sf::read_sf() and produced the HTML table within the popup using the htmlTable package after reading How to add an html table to leaflet popup.
# load necessary package
library( htmlTable )
library( leaflet )
library( sf )
# load necessary data
blahTest <-
read_sf(
dsn = "test.geojson"
, layer = "OGRGeoJSON"
)
# map data values to colors
fpal <- colorFactor( palette = "viridis", domain = blahTest$class)
# create map
my.map <-
leaflet( data = blahTest ) %>%
addTiles() %>%
addPolygons( stroke = FALSE
, smoothFactor = 0.3
, fillOpacity = 1
, color = ~fpal( class )
, popup = paste0(
"<b>Class: </b>"
, blahTest$class
, "<br>"
, "<b>Coordinates: </b>"
, "<br>"
, lapply(
X = blahTest$geometry
, FUN = function( i )
htmlTable(
x = i[[1]]
, header = c( "Longitude", "Latitude" )
)
)
) ) %>%
addLegend( pal = fpal
, values = ~class
, labels = ~class
, title = "Legend"
, position = "topright"
, opacity = 1.0 )
# view map
my.map
# end of script #