[paparazzi-commits] [4202] New naming policy for Google tiles

[Pascal Brisset]

Revision: 4202
          http://svn.sv.gnu.org/viewvc/?view=rev&root=paparazzi&revision=4202
Author:   hecto
Date:     2009-09-25 19:42:36 +0000 (Fri, 25 Sep 2009)
Log Message:
-----------
 New naming policy for Google tiles

Modified Paths:
--------------
    paparazzi3/trunk/sw/lib/ocaml/gm.ml

Modified: paparazzi3/trunk/sw/lib/ocaml/gm.ml
===================================================================
--- paparazzi3/trunk/sw/lib/ocaml/gm.ml 2009-09-24 17:36:27 UTC (rev 4201)
+++ paparazzi3/trunk/sw/lib/ocaml/gm.ml 2009-09-25 19:42:36 UTC (rev 4202)
@@ -154,9 +154,27 @@
       raise Not_found in
   loop 0
 
+(** Translate the old quadtree naming policy into new (x,y) coordinates
+    if z is the zoom level, 0 <= x, y < 2^z are the coordinates of the tile *)
+let xyz_of_qsrt = fun s ->
+  let x = ref 0
+  and y = ref 0
+  and n = String.length s in
+  for i = 1 to n - 1 do (* Skip the first t *)
+    x := !x * 2;
+    y := !y * 2;
+    match s.[i] with
+      'q' -> ()
+    | 'r' -> incr x
+    | 's' -> incr x; incr y
+    | 't' -> incr y
+    | _ -> failwith "xy_of_qsrt"
+  done;
+  (!x, !y, n-1)
 
 let google_maps_url = fun s -> 
-  sprintf "http://khm.google.com/kh?n=404&v=3&t=%s"; s
+  let (x, y, z) = xyz_of_qsrt s in
+  sprintf "http://khm0.google.com/kh/v=45&x=%d&s=&y=%d&z=%d"; x y z
 
 exception Not_available
 
@@ -164,6 +182,7 @@
 
 let remove_last_char = fun s -> String.sub s 0 (String.length s - 1)
 
+
 let get_image = fun key ->
   try get_from_cache key with
     Not_found ->