[R-sig-Geo] A leaflet question

[Ben Tupper]

Hi Erin,

I think it has to do with the naming convention.  If your map object is
called "plot", then you should expect the input to have the name
"plot_click" which you can access with `input$plot_click` You have looked
for input$plot_marker_click which hasn't been defined.

I'm not sure why nearPoints() throws an error in this case.


```
library(tigris)
library(leaflet)
library(sf)
options(tigris_use_cache = TRUE)
#Getting the data
tarrant <- tracts(state="TX",county="Tarrant",cb=TRUE)
tarrant_sp <- as(tarrant,"Spatial")

#Set up ui
ui <- fluidPage(
  leafletOutput("plot"),
  tableOutput("data")
)
#Set up server
server <- function(input, output, session) {
  #Draw map
  output$plot <- renderLeaflet({
    leaflet(tarrant_sp) %>% addTiles() %>%
      addPolygons(label=~TRACTCE)
  })
  #allegedly grab market clicks
  output$data <- renderTable({
    click <- input$plot_click
    cat("click class = ", class(click), "\n")
    cat(str(click), "\n")
    print(nearPoints(tarrant_sp, click))
  })
}
shinyApp(ui,server)
```

On Wed, Jun 1, 2022 at 10:15 AM Erin Hodgess <erinm.hodgess using gmail.com>
wrote:

> Thank you for your kind response.
>
> Here is my code:
>
> library(tigris)
> library(leaflet)
> library(sf)
>
> #Getting the data
> tarrant <- tracts(state="TX",county="Tarrant",cb=TRUE)
> tarrant_sp <- as(tarrant,"Spatial")
>
> #Set up ui
> ui <- fluidPage(
>   leafletOutput("plot"),
>   tableOutput("data")
> )
> #Set up server
> server <- function(input, output, session) {
>   #Draw map
>   output$plot <- renderLeaflet({
>   leaflet(tarrant_sp) %>% addTiles() %>%
>   addPolygons(label=~TRACTCE)
> })
>   #allegedly grab market clicks
>   output$data <- renderTable({
>     nearPoints(tarrant_sp, input$plot_marker_click)
>     print(input$plot_marker_click)
>   })
> }
> shinyApp(ui,server)
>
> I would like to get the values from the click and make calculations based
> on the tracts selected.  However, nothing is appearing in the
> input$plot_marker_click.
>
> Any suggestions much appreciated.
>
> Sincerely,
> Erin
>
>
> Erin Hodgess, PhD
> mailto: erinm.hodgess using gmail.com
>
>
> On Wed, Jun 1, 2022 at 9:03 AM Ben Tupper <btupper using bigelow.org> wrote:
>
>> Hi Erin,
>>
>> This is a great place to ask questions - especially if you provide a
>> reproducible example.
>>
>> Cheers,
>> Ben
>>
>> On Wed, Jun 1, 2022 at 8:24 AM Erin Hodgess <erinm.hodgess using gmail.com>
>> wrote:
>>
>>> Hello everyone;
>>>
>>> Can I ask a leaflet question here, please, or is that a topic for RStudio
>>> Community?
>>>
>>> Thanks,
>>> Erin
>>> --
>>> Erin Hodgess, PhD
>>> mailto: erinm.hodgess using gmail.com
>>>
>>>         [[alternative HTML version deleted]]
>>>
>>> _______________________________________________
>>> R-sig-Geo mailing list
>>> R-sig-Geo using r-project.org
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>
>>
>>
>> --
>> Ben Tupper (he/him)
>> Bigelow Laboratory for Ocean Science
>> East Boothbay, Maine
>> http://www.bigelow.org/
>> https://eco.bigelow.org
>>
>>

-- 
Ben Tupper (he/him)
Bigelow Laboratory for Ocean Science
East Boothbay, Maine
http://www.bigelow.org/
https://eco.bigelow.org

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