refactor: improve filtering logic and map initialization

Co-authored-by: aider (deepseek/deepseek-chat) <aider@aider.chat>

app.R

@@ -362,9 +362,8 @@ server <- function(input, output, session) {
   # Initialize filteredOwners with all owners
   filteredOwners <- reactiveVal(owners)
   
-  # Update filtered owners when filter button is clicked
-  observeEvent(input$filterButton, {
-    # Start with all owners
+  # Function to filter owners based on inputs
+  filterOwners <- function() {
     filtered <- owners
     
     # Filter by subdivision if specified
@@ -392,13 +391,28 @@ server <- function(input, output, session) {
         filter(grepl(input$location, location, ignore.case = TRUE))
     }
     
-    filteredOwners(filtered)
+    return(filtered)
+  }
+  
+  # Update filtered owners when filter button is clicked
+  observeEvent(input$filterButton, {
+    filteredOwners(filterOwners())
   })
   
-  # Also update when the app starts
+  # Also update when any of the filter inputs change
   observe({
-    # Trigger initial update
-    filteredOwners(owners)
+    # Track dependencies
+    input$name
+    input$location
+    input$sub_name
+    
+    # Update filtered owners, but only if the filter button has been clicked at least once
+    # To prevent immediate filtering on app start
+    if (!is.null(input$filterButton)) {
+      if (input$filterButton > 0) {
+        filteredOwners(filterOwners())
+      }
+    }
   })
   
   mean_lat <- reactive({