diff -Nur -X/home/thue/freeciv-dev/no.freeciv freeciv/client/gui-gtk/mapview.c display_bug2/client/gui-gtk/mapview.c
--- freeciv/client/gui-gtk/mapview.c	Fri Apr 14 12:52:35 2000
+++ display_bug2/client/gui-gtk/mapview.c	Sat Apr 15 18:33:27 2000
@@ -710,10 +710,11 @@
 **************************************************************************/
 void overview_update_tile(int x, int y)
 {
-  int pos=x+map.xsize/2-(map_view_x0+map_canvas_store_twidth/2);
+  int pos = x + map.xsize/2 - (map_view_x0 + map_canvas_store_twidth/2);
   
-  if(pos>=map.xsize)
-    pos-=map.xsize;
+  pos %= map.xsize;
+  if (pos < 0)
+    pos += map.xsize;
   
   set_overview_tile_foreground_color(x, y);
   gdk_draw_rectangle( overview_canvas_store, fill_bg_gc, TRUE, x*2, y*2,
diff -Nur -X/home/thue/freeciv-dev/no.freeciv freeciv/client/gui-xaw/mapview.c display_bug2/client/gui-xaw/mapview.c
--- freeciv/client/gui-xaw/mapview.c	Fri Apr 14 12:52:36 2000
+++ display_bug2/client/gui-xaw/mapview.c	Sat Apr 15 18:34:07 2000
@@ -680,10 +680,11 @@
 **************************************************************************/
 void overview_update_tile(int x, int y)
 {
-  int pos=x+map.xsize/2-(map_view_x0+map_canvas_store_twidth/2);
+  int pos = x + map.xsize/2 - (map_view_x0 + map_canvas_store_twidth/2);
   
-  if(pos>=map.xsize)
-    pos-=map.xsize;
+  pos %= map.xsize;
+  if (pos < 0)
+    pos += map.xsize;
   
   set_overview_tile_foreground_color(x, y);
   XFillRectangle(display, overview_canvas_store, fill_bg_gc, x*2, y*2,