url have been updated as old one did not work anymore
Here is an explanation on how google map server works, it took me some time to undertand it, when i finnaly found that it is really simple!
google map server
or etc... is a quadtree of 256*256 jpg:
NB: I play by computing and approximation of number of jpg handled by google maps server about 2*4^19 jpg(256*256) or 2^39!! Lets look at the following url:
http://kh1.google.fr/kh?v=20&t=tqnew URLexplanation of parameter:
v : length of t parameter can be higher but cannot be lesser than t parameter lenght (so you can let it to 20)
t : jpg location in the quad tree begining with "t"The above url t parameter means:
first jpg of the first tree level "q"
second jpg of the first tree level "r"
third jpg of the first tree level "s"
fourth jpg of the first tree level "t"how it is divided:
TSeach level is than subdivided in 4 same way:
qq means first sub jpg of the first jpgyou may better understand with this picture :So to have the first quarter of the earth:
http://kh1.google.fr/kh?v=20&t=tqhttp://kh0.google.com/kh?v=3&t=tqand the first quarter of the first quarter: http://kh1.google.fr/kh?v=20&t=tqqhttp://kh0.google.com/kh?v=3&t=tqq
it is easy to convert latitude and longitude to quarter you can see a demo online there:http://demo.dzzd.net/GMAP/
If you are interrested in the demo source code just right click on your browser and select view source there is no outside files, the whole source including jscript is in the the html source code.