title: Output not showing in Shiny
body: <p>I complied the below code to show the output as a GGmap in R Script. The code runs fine but the output is not shown.
  Could anyone please be kind enough to assist. I been trying to figure out the error but still yet not been able to. Appreciate it if anyone could help me. Thank you in advance.</p>
  <pre><code>    #### Below Code ####
      ## Libraries
  
     library(ggmap)
     library(shiny)
              
      bbox = c(left=-95.8, bottom=29.4, right=-95.0, top=30.0)
      map &lt;- get_stamenmap(bbox, zoom = 10, source=&quot;stamen&quot;)
      
      ui &lt;- fluidPage(
        titlePanel(&quot;Crime Offences&quot;),
        sidebarPanel('Navigator',
                     checkboxGroupInput(&quot;crime_type&quot;, label = &quot;Select offense type:&quot;,
                                        choices = list(&quot;Aggravated Assault&quot; = 'aggravated assault',
                                                       &quot;Auto Theft&quot; = 'auto theft',
                                                       &quot;Burglary&quot; = 'burglary',
                                                       &quot;Murder&quot; = 'murder',
                                                       &quot;Rape&quot; = 'rape',
                                                       &quot;Robbery&quot; = 'robbery'),
                                        selected = 'Intel'),
                     dateRangeInput(&quot;date_range&quot;, label = &quot;Select time period:&quot;,
                                    start = &quot;2010-01-01&quot;,
                                    end = &quot;2010-08-31&quot;,
                                    min = &quot;2010-01-01&quot;,
                                    max = &quot;2010-08-31&quot;,
                                    format = &quot;mm/dd'yy&quot;,
                                    separator = &quot; - &quot;)),
        
        
        mainPanel('Crime Data Information',
                  plotOutput(&quot;crime_data_final&quot;)),
        position = 'left')
      
      
      server &lt;- function(input, output){
        output$crime_data_final &lt;- renderPlot(
          
          ggmap(map) + stat_density2d(data = subset(crime_data, offense == input$crime_type),
                                      aes(x = &quot;date&quot;, y = input$crime_type) +
            scale_fill_gradient(low = &quot;green&quot;, high = &quot;red&quot;) +
            scale_alpha_continuous(range = c(0, 0.8)) +
            geom_point(data = subset(crime_data, offense == input$crime_type),
                       aes(x = &quot;date&quot;, y = input$crime_type), size = 0.5) + 
            guides(fill = FALSE, alpha = FALSE) +
            ggtitle('Crime in Houston TX',
                    subtitle = 'Murders are concentrated around two areas in the city'))
        )
      }
      
      ## Executing the app
      
      shinyApp(ui = ui, server = server)
      
      
  </code></pre>
  <p>Below is the output</p>
  <p><img src="https://i.stack.imgur.com/7Ck6H.png" alt="example output" /></p>