ui.R

# code for rendering the application

library(leaflet) # base for shiny map display

ui <- fluidPage(

  # add the title to the top of the page
  titlePanel("BART Passenger Heatmap"),

  # the main portion of the app
  fluidRow(

    # the rendered map
    column(width = 10,
      leafletOutput("basemap", height = 1000)
    ),

    # the buttons, all together in one centered column
    column(width = 2, align = "center",

      # selector for the desired date range
      # minimums and maximums are determined from the input data
      dateRangeInput("dateRange",
                     label = "Date Range (YYYY-MM-DD)",
                     start = minDate,
                     end = maxDate,
                     min = minDate,
                     max = maxDate),

      # checkboxes for the desired times
      # we use checkboxes so users can pick non-contiguous ranges
      checkboxGroupInput("timeRange",
                         label = "Hours",
                         choiceNames = twelveHour,
                         choiceValues = seq(from = 0, to = 23, by = 1),
                         selected = seq(from = 0, to = 23, by = 1)),

      # update button, attempts to update the map when pressed
      actionButton("updateDatetime", label = "Update")
    )
  )
)