diff --git a/pkgs/maps/main.fnl b/pkgs/maps/main.fnl
index dc35283..2c6f418 100644
--- a/pkgs/maps/main.fnl
+++ b/pkgs/maps/main.fnl
@@ -71,7 +71,7 @@ label.readout {
   (collect [k v (pairs table2) &into table1]
     k v))
 
-(var map-surface nil)
+
 
 (fn map-bounds [lat lon zoom]
   (let [num-tiles-x (+ 1 (math.ceil (/ map-width tile-size)))
@@ -122,6 +122,7 @@ label.readout {
       (g:stroke)
       map-surface)))
 
+(var map-surface nil)
 
 (fn on-osm-draw [widget g]
   (when (not map-surface)
@@ -177,16 +178,24 @@ label.readout {
 
 
 (fn update-app-state [new-vals]
-  (merge app-state new-vals)
-  (each [name widget (pairs state-widgets)]
-    (case name
-      :speed (widget:set_label
-              (string.format "%.1f km/h" (* app-state.speed 3.6)))
-      :osm (: (widget:get_window) :invalidate_rect nil)
-      :arrow (: (widget:get_window) :invalidate_rect nil)
-      :time (widget:set_label
-             (hhmmss (+ utc-offset app-state.time-of-day)))
-      )))
+  (let [old-bounds
+        (map-bounds app-state.lat app-state.lon app-state.zoom)]
+    (merge app-state new-vals)
+    (let [bounds
+          (map-bounds app-state.lat app-state.lon app-state.zoom)]
+      (when (or
+             (not (= old-bounds.min.x bounds.min.x))
+             (not (= old-bounds.min.y bounds.min.y)))
+        (set map-surface nil)))
+    (each [name widget (pairs state-widgets)]
+      (case name
+        :speed (widget:set_label
+                (string.format "%.1f km/h" (* app-state.speed 3.6)))
+        :osm (: (widget:get_window) :invalidate_rect nil)
+        :arrow (: (widget:get_window) :invalidate_rect nil)
+        :time (widget:set_label
+               (hhmmss (+ utc-offset app-state.time-of-day)))
+        ))))
 
 
 (fn readouts []