Improved Graph

The color bar for points in the graph changes adjusts to the selected date range.

dashboardShiny/app.R

@@ -191,29 +191,34 @@ server <- function(input, output, session) {
   
   ## 3. Plot salinity profile for selected point  ------------------------------
   
+  ### Create a reactive function to compute color scale limits
+  ### based on the selected date range
+  color_scale_limits <- reactive({
+    min_date <- min(filteredData()$Date)
+    max_date <- max(filteredData()$Date)
+    return(c(min_date, max_date))
+  })
+  
   ### When a point is selected on the map, display the salinity profile(s)
   observeEvent(input$myMap_marker_click, {
-    
     event <- input$myMap_marker_click
-    df <- filteredData() %>% 
-      filter(Station_ID == event$id)
-    
     output$selected_id <- renderText({
       paste("Selected Location: ", event$id)
     })
-    
-    output$graph <- renderPlotly(
-      plot_ly(data = df, x = ~Value, y = ~(-1*Depth), 
-              type = 'scatter', mode = 'markers', text = ~Date, colors = "viridis",
-              marker = list(size = 5, color = ~Date, colors = "viridis")) %>%
-      layout(
-        title = "Salinity profile plot",
-        xaxis = list(title = "Salinity (PSU)"),
-        yaxis = list(title = "Depth (m)")
-      )
-    )
+    profile_plot <- filteredData() %>% 
+      filter(Station_ID == event$id) %>% 
+      mutate(Depth = -1*Depth) %>% 
+      ggplot() +
+        geom_point(
+          mapping = aes(x = Value, y = Depth, color = Date), 
+          show.legend = FALSE) +
+        scale_color_gradient(
+          low = "gold", high = "maroon", 
+          limits = color_scale_limits()) +
+        labs(x = "Salinity (PSU)", y = "Depth (m)") +
+        theme(legend.position = "none")
+    output$graph <- renderPlotly(ggplotly(profile_plot))
   })
-
 }
 
 # Initialize App ===============================================================