I know this question has been asked a lot of time, but every question varies according to the code/purpose. That being said I am creating shiny app that:
sf_object) "filemap".mapview).three variables from the same shapefile as x and y axis arguments for some plotly timeseries plot. But for now this is not part of the question.I am getting this error while running the app:
Error in input$Temp : Can't access reactive value 'Temp' outside of reactive consumer. i Do you need to wrap inside reactive() or observe()? Warning: Error in updateSelectInput: object 'Temp_map' not found
Sample Data (part of the data from the shapefile to be uploaded):
structure(list(Info = c(NA_character_, NA_character_, NA_character_,
NA_character_, NA_character_), tmean = c(22.2395992279053, 22.7657985687256,
24.4260005950928, 19.601001739502, 17.5659999847412), CITYNAME = c("NORTH LAUDERDALE",
"NORTH LAUDERDALE", "NORTH LAUDERDALE", "NORTH LAUDERDALE", "NORTH LAUDERDALE"
), Model = c("PRISM", "PRISM", "PRISM", "PRISM", "PRISM"), Variable = c("tmean",
"tmean", "tmean", "tmean", "tmean"), Datatype = c("provisional",
"provisional", "stable", "stable", "stable"), Resolution = c("4kmM3",
"4kmM3", "4kmM3", "4kmM3", "4kmM3"), year = c(2021L, 2021L, 1980L,
1980L, 1980L), month = c(11L, 12L, 0L, 1L, 2L), TMin = c(0, 0,
0, 0, 0), TMax = c(0, 0, 0, 0, 0), geometry = structure(list(
structure(c(-80.2083333327448, 26.2083333333333), class = c("XY",
"POINT", "sfg")), structure(c(-80.2083333327448, 26.2083333333333
), class = c("XY", "POINT", "sfg")), structure(c(-80.2083333327448,
26.2083333333333), class = c("XY", "POINT", "sfg")), structure(c(-80.2083333327448,
26.2083333333333), class = c("XY", "POINT", "sfg")), structure(c(-80.2083333327448,
26.2083333333333), class = c("XY", "POINT", "sfg"))), class = c("sfc_POINT",
"sfc"), precision = 0, bbox = structure(c(xmin = -80.2083333327448,
ymin = 26.2083333333333, xmax = -80.2083333327448, ymax = 26.2083333333333
), class = "bbox"), crs = structure(list(input = "WGS 84", wkt = "GEOGCRS[\"WGS 84\",\n DATUM[\"World Geodetic System 1984\",\n ELLIPSOID[\"WGS 84\",6378137,298.257223563,\n LENGTHUNIT[\"metre\",1]]],\n PRIMEM[\"Greenwich\",0,\n ANGLEUNIT[\"degree\",0.0174532925199433]],\n CS[ellipsoidal,2],\n AXIS[\"latitude\",north,\n ORDER[1],\n ANGLEUNIT[\"degree\",0.0174532925199433]],\n AXIS[\"longitude\",east,\n ORDER[2],\n ANGLEUNIT[\"degree\",0.0174532925199433]],\n ID[\"EPSG\",4326]]"), class = "crs"), n_empty = 0L)), row.names = c(NA,
-5L), class = c("sf", "data.frame"), sf_column = "geometry", agr = structure(c(Info = NA_integer_,
tmean = NA_integer_, CITYNAME = NA_integer_, Model = NA_integer_,
Variable = NA_integer_, Datatype = NA_integer_, Resolution = NA_integer_,
year = NA_integer_, month = NA_integer_, TMin = NA_integer_,
TMax = NA_integer_), class = "factor", .Label = c("constant",
"aggregate", "identity")))
UI
library(shiny)
library(shinydashboard)
library(shinythemes)
library(tidyverse)
library(RColorBrewer)
library(png)
library(shinyWidgets)
library(sf)
library(leaflet)
# Define UI for application that draws an interactive ggplot
options(shiny.maxRequestSize=30*1024^2)
ui = navbarPage("Temperature Analysis", theme = shinytheme("sandstone"),
tabPanel("Introduction",
icon = icon("info"),
img(src="tenor (1).gif", align = "topleft",height='90px',width='90px'),
div(p(h1("Objective"),style="text-align: justify;", "The app focuses on analyzing air temperature trends over a 40 year period. The purpose was to see how much the climate has changed over time. Second objective of this project was to make a Shiny app that serves three purposes for the user:")),
p("1. The user can upload a shapefile and the app will return a Chloropleth map."),
p("2. Based on the uploaded shapefile, the app will return a interactive timeseries plot."),
p("3. Based on the uploaded shapefile, the app will return the regression results and an interactive resultant regression plot."),
uiOutput("all")),
tabPanel("Temperature Timeseries Plot",
icon = icon("chart-area"),
img(src="tenor (2).gif", align = "topleft",height='90px',width='90px'),
sidebarLayout(sidebarPanel(fileInput("filemap", label = "Input Shapefile
(.shp,.dbf,.sbn,.sbx,.shx,.prj)",
multiple=TRUE,
accept = c(".shp",
".dbf",
".sbn",
".sbx",
".shx",
".prj"))),
mainPanel(selectInput(inputId = "Temp", label = "Select Temperature Variable", choices = c("Mean Temperature" = "TMean", "Minimum Temperature" = "TMin", "Maximum Temperature" = "TMax")),
leafletOutput("mapview")))))
Server
# Tell the server how to assemble inputs into outputs
server = function(input, output, session) {
# Read-in shapefile function
Read_Shapefile = function(shp_path) {
infiles = shp_path$datapath # get the location of files
dir = unique(dirname(infiles)) # get the directory
outfiles = file.path(dir, shp_path$name) # create new path name
name = strsplit(shp_path$name[1], "\\.")[[1]][1] # strip name
purrr::walk2(infiles, outfiles, ~file.rename(.x, .y)) # rename files
x = read_sf(file.path(dir, paste0(name, ".shp"))) # read-in shapefile
return(x)
}
# Read-shapefile once user submits files
observe({
req(input$filemap)
Temp_map = Read_Shapefile(input$filemap)})
# Code for allowing the user to select the variables/columns of interest to map
# info = eventReactive(input$Temp, {
# req(Temp_map())
# t = Temp_map()
# t
# })
observeEvent(input$Temp, {
updateSelectInput(session,"Temp", "Please select the temperature variable to map:", choices = names(Temp_map))
}) # Allows the user to select the column/variable to map based on uploaded shapefile (Temp_map)
pal_fun = colorQuantile("YlOrRd", NULL, n = 5) # Define color palette and classes
t_popup = paste0("Air Temperature", input$Temp) # Popup depends on the "Temp" variable selected
output$mapview = renderLeaflet({(input$Temp) %>% # Map depends on the "Temp" variable selected
addPolygons(
stroke = FALSE, # remove polygon borders
fillColor = ~pal_fun(input$Temp), # set fill color with function from above and value
fillOpacity = 0.8, smoothFactor = 0.5, # make it nicer
popup = t_popup) # add popup
})
}
The problem was caused by having two observe functions. Removing the second one removes the error.
Server
Read-in shapefile function
Read_Shapefile = function(shp_path) {
infiles = shp_path$datapath # get the location of files
dir = unique(dirname(infiles)) # get the directory
outfiles = file.path(dir, shp_path$name) # create new path name
name = strsplit(shp_path$name[1], "\\.")[[1]][1] # strip name
purrr::walk2(infiles, outfiles, ~file.rename(.x, .y)) # rename files
x = read_sf(file.path(dir, paste0(name, ".shp"))) # read-in shapefile
return(x)
}
# Read-shapefile once user submits files
observe({
req(input$filemap)
Temp_map = Read_Shapefile(input$filemap)
# # Code for allowing the user to select the variables/columns of interest to map
# observe({
# req(input$Temp)
# updateSelectInput(session,"Temp", "Please select the temperature variable to map:", choices = names(Temp_map))
# }) # Allows the user to select the column/variable to map based on uploaded shapefile (Temp_map)
pal_fun = colorQuantile("YlOrRd", NULL, n = 5) # Define color palette and classes
t_popup = paste0("Air Temperature", input$Temp) # Popup depends on the "Temp" variable selected
output$mapview = renderLeaflet({(input$Temp) %>% # Map depends on the "Temp" variable selected
addPolygons(
stroke = FALSE, # remove polygon borders
fillColor = ~pal_fun(input$Temp), # set fill color with function from above and value
fillOpacity = 0.8, smoothFactor = 0.5, # make it nicer
popup = t_popup) # add popup
})
})
}