diff --git a/sw/ground_segment/cockpit/gcs.ml b/sw/ground_segment/cockpit/gcs.ml
index b51807bbce..4ef18fbaea 100644
--- a/sw/ground_segment/cockpit/gcs.ml
+++ b/sw/ground_segment/cockpit/gcs.ml
@@ -174,10 +174,11 @@ end
 (************ Google, OSM Maps handling *****************************************)
 module GM = struct
   (** Fill the visible background with Google, OSM tiles *)
+  let zoomlevel = ref 18
   let fill_tiles = fun geomap ->
     match geomap#georef with
       None -> ()
-    | Some _ -> TodoList.add (fun () -> MapGoogle.fill_window geomap)
+    | Some _ -> TodoList.add (fun () -> MapGoogle.fill_window geomap !zoomlevel)
 
   let auto = ref false
   let update = fun geomap ->
@@ -197,7 +198,7 @@ module GM = struct
            posn_long = min geo1.posn_long geo2.posn_long }
     and ne = { posn_lat = max geo1.posn_lat geo2.posn_lat;
            posn_long = max geo1.posn_long geo2.posn_long } in
-    let pix = MapGoogle.pixbuf sw ne in
+    let pix = MapGoogle.pixbuf sw ne !zoomlevel in
     let nw = { posn_lat = ne.posn_lat; posn_long = sw.posn_long }
     and se = { posn_lat = sw.posn_lat; posn_long = ne.posn_long } in
     save_map geomap ~projection:"Mercator" pix nw se
@@ -347,6 +348,7 @@ let options =
    "-edit", Arg.Unit (fun () -> edit := true; layout_file := "editor.xml"), "Flight plan editor";
    "-fullscreen", Arg.Set fullscreen, "Fullscreen window";
    "-maps_fill", Arg.Set GM.auto, "Automatically start loading background maps";
+   "-maps_zoom", Arg.Set_int GM.zoomlevel, "Background maps zoomlevel (default: 18, max: 22)";
    "-ign", Arg.String (fun s -> ign:=true; IGN.data_path := s), "IGN tiles path";
    "-lambertIIe", Arg.Unit (fun () -> projection:=G.LambertIIe),"Switch to LambertIIe projection";
    "-layout", Arg.Set_string layout_file, (sprintf "<XML layout specification> GUI layout. Default: %s" !layout_file);
@@ -470,7 +472,7 @@ let create_geomap = fun switch_fullscreen editor_frame ->
   (** Separate from A/C menus *)
   ignore (geomap#factory#add_separator ());
 
-  (** Set the initial soom *)
+  (** Set the initial zoom *)
   geomap#zoom !zoom;
   geomap, menu_fact
 
diff --git a/sw/lib/ocaml/gm.ml b/sw/lib/ocaml/gm.ml
index 31b9cff1cc..3a92869d0c 100644
--- a/sw/lib/ocaml/gm.ml
+++ b/sw/lib/ocaml/gm.ml
@@ -28,7 +28,7 @@ open Latlong
 open Printf
 
 let tile_size = 256, 256
-let zoom_max = 18
+let zoom_max = 22
 
 let cache_path = ref "/var/tmp"
 
diff --git a/sw/lib/ocaml/mapGoogle.ml b/sw/lib/ocaml/mapGoogle.ml
index 650ec1ddf5..874b2c15e5 100644
--- a/sw/lib/ocaml/mapGoogle.ml
+++ b/sw/lib/ocaml/mapGoogle.ml
@@ -109,7 +109,7 @@ let display_tile = fun (geomap:MapCanvas.widget) wgs84 ->
 exception New_displayed of int
 (** [New_displayed zoom] Raised when a new is loadded *)
 
-let fill_window = fun (geomap:MapCanvas.widget) ->
+let fill_window = fun (geomap:MapCanvas.widget) zoomlevel ->
   (** First estimate the coverage of the window *)
   let width_c, height_c = Gdk.Drawable.get_size geomap#canvas#misc#window
   and (xc0, yc0) = geomap#canvas#get_scroll_offsets in
@@ -136,7 +136,7 @@ let fill_window = fun (geomap:MapCanvas.widget) ->
 	    if zoom = 1 then
 	      let tile, image = Gm.get_image key in
 	      display_the_tile geomap tile image;
-	      raise (New_displayed (19-String.length tile.Gm.key))
+	      raise (New_displayed (zoomlevel+1-String.length tile.Gm.key))
 	    else begin
 	      trees.(i) <- Node (Array.create 4 Empty);
 	      loop twest tsouth tsize trees i zoom key
@@ -158,7 +158,7 @@ let fill_window = fun (geomap:MapCanvas.widget) ->
 	New_displayed z when z = zoom ->
 	  trees.(i) <- Tile
       | Gm.Not_available -> () in
-  loop (-1.) (-1.)  2. [|gm_tiles|] 0 18 "t"
+  loop (-1.) (-1.)  2. [|gm_tiles|] 0 zoomlevel "t"
 
 
 exception To_copy of int * string
@@ -172,7 +172,7 @@ let gdk_pixbuf_safe_copy_area ~dest ~dest_x ~dest_y ~width ~height ~src_x ~src_y
   and height = min height (GdkPixbuf.get_height dest -dest_y) in
   GdkPixbuf.copy_area ~dest ~dest_x ~dest_y ~width ~height ~src_x ~src_y pixbuf
 
-let pixbuf = fun sw ne ->
+let pixbuf = fun sw ne zoomlevel->
   assert (sw.LL.posn_lat < ne.LL.posn_lat);
   assert (sw.LL.posn_long < ne.LL.posn_long);
   let west = sw.LL.posn_long /. LL.pi
@@ -191,7 +191,7 @@ let pixbuf = fun sw ne ->
 	if zoom = 1
 	then
 	  let tile, image = Gm.get_image key in
-	  raise (To_copy (19-String.length tile.Gm.key, image))
+	  raise (To_copy (zoomlevel+1-String.length tile.Gm.key, image))
 	else begin
 	  let continue = fun j tw ts ->
 	    loop tw ts tsize2 (zoom-1) (key^String.make 1 (char_of j)) in
@@ -210,5 +210,5 @@ let pixbuf = fun sw ne ->
 	  let pixbuf = GdkPixbuf.from_file image in
 	  gdk_pixbuf_safe_copy_area ~dest ~dest_x ~dest_y ~width ~height:width ~src_x ~src_y pixbuf
       | Gm.Not_available -> () in
-  loop (-1.) (-1.)  2. 18 "t";
+  loop (-1.) (-1.)  2. zoomlevel "t";
   dest
diff --git a/sw/lib/ocaml/mapGoogle.mli b/sw/lib/ocaml/mapGoogle.mli
index 0255098cac..398b38bf24 100644
--- a/sw/lib/ocaml/mapGoogle.mli
+++ b/sw/lib/ocaml/mapGoogle.mli
@@ -25,8 +25,8 @@
 val display_tile : MapCanvas.widget -> Latlong.geographic -> unit
 (** Displaying the Google Maps tile around the given point (zoom=1) *)
 
-val fill_window : MapCanvas.widget -> unit
-(** Filling the canvas window with Google Maps tiles *)
+val fill_window : MapCanvas.widget -> int -> unit
+(** Filling the canvas window with Google Maps tiles at given zoomlevel*)
 
-val pixbuf : Latlong.geographic -> Latlong.geographic -> GdkPixbuf.pixbuf
-(** [pixbuf south_west north_east] Returns a map background of the given area *)
+val pixbuf : Latlong.geographic -> Latlong.geographic -> int -> GdkPixbuf.pixbuf
+(** [pixbuf south_west north_east zoomlevel] Returns a map background of the given area *)