[R-sig-Geo] A leaflet question

[Erin Hodgess]

Thank you so much!

Here is the error that I get from nearPoints:
nearPoints requires a click/hover/double-click object with x and y values.

The "click" from the leaflet does not have the same components as the
"click" from a regular plot.

Erin Hodgess, PhD
mailto: erinm.hodgess using gmail.com


On Wed, Jun 1, 2022 at 2:16 PM Ben Tupper <btupper using bigelow.org> wrote:

> 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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