Getting mapedit to work with Shiny and leaflet

[GreyMerchant]

Hi,

Thanks for this package. The project looks amazing and will be a phenomenal help going forward. I am struggling a bit to get everything to work and I hope I may ask for help here.

So I want to get this functionality directly in Shiny: what_we_created <- mapview() %>% editMap()

I essentially just want to be able to call up a leaflet map and allow a person to draw a spatial polygon and get the shiny application to save that information in the background.

I am able to get the package to work with this code on my server bit of my R code:

shinyServer(function(input, output, session) { #callModule creates a small module CM_edit <- callModule(editMod, "test-edit", m, record = TRUE) output$edited <- renderLeaflet({ req(CM_edit()$finished) mapview(CM_edit()$finished)@map }) })

However it is not the same as editMap() where you can hit "done" and get it to write to a df (I am also not sure if I am doing it entirely correct above). Is there some way to have this exact functionality in shiny?

Any other help and tips would be appreciated! I am finding the syntax a bit strange still.

[timelyportfolio]

@GreyMerchant thanks so much for the issue. There are different opinions on whether a question like this belongs in Github issues, but for mapedit Github issues is the encouraged forum. I'm travelling currently, but I'll try to post an example once I get back fully online. Glad you are using mapedit!

[mrjoh3]

Hi @GreyMerchant I hope this is what you are talking about. Below is my minimum example of using mapedit and leaflet with a button to save edits. In this case the button will also save the created spatial dataframe to a geojson file.

library(shiny)
library(leaflet)
library(mapedit)
library(sf)

map <- leaflet() %>%
    addTiles()

ui <- fluidPage(

    # Application title
    titlePanel("Minimal Shiny Leaflet Mapedit"),

    # Sidebar with a ui for grabbing mapedit data
    sidebarLayout(
        sidebarPanel(
            actionButton('save', 'Save from Map')
        ),

        # add map
        mainPanel(
            editModUI("map")
        )
    )
)

server <- function(input, output) {

    edits <- callModule(
        editMod,
        leafmap = map,
        id = "map"
    )

    observeEvent(input$save, {

        geom <- edits()$finished

        if (!is.null(geom)) {
            assign('new_geom', geom, envir = .GlobalEnv)
            sf::write_sf(geom, 'new_geom.geojson', delete_layer = TRUE, delete_dsn = TRUE)
        }

    })
}

# Run the application 
shinyApp(ui = ui, server = server)

[mrjoh3]

if you also wanted to manipulate the leaflet map you can use leafletProxy in the normal way. For example:

        leafletProxy("map-map") %>%
            addPolygons(data = geom, color = 'red')

notice the map-map reference? this is due the the module name spacing, so you could use ns() to make this more dynamic.

[GreyMerchant]

Thank you for the responses :) This reads far easier than the code I was looking at. Thank you so much!

[timelyportfolio]

going to close... please reopen if we missed anything. Thanks for using mapedit.