问题
i got a link which try to explain how to store image tiles in file system but not very clear to me. here is the url http://build-failed.blogspot.in/2012/11/zoomable-image-with-leaflet.html
just see this image
just seen many sub folder has been created as per image but do not understand what they try to point out with arrow images ?
how this eso / «z» / «x» / «y».jpg is related with images folder structure?
1) why zero folder is consider as z ?
2) why zero and one sub folder in parent folder called one is consider as x ?
1) why 0.png and 1.png images are consider as y ?
the above three things is not clear due to lack of explanation. what is the relation there ?
if some one already knows it or do understand then please share the knowledge with me. thanks
回答1:
Ok I'll try to explain.
First z = zoom level, x=longitude, y=latitude
Longitude and latitude are not real value taken from the map projection but grid indexes.
The way you store the tiles is like this:
- First parent folder: z (zoom level)
- Child folders: all x at this zoom level
- Images names: all y at this x position and this zoom level
If you want to store for instance the following tile: /0/0/0.png
- Folder: 0
- Subfolder: 0
- 0.png
At zoom level 0, habitually there is only on tile for the whole world so only a subfolder 0 (for the x) and an image 0.png (for the y). At each zoom level the number of images increase exponentially.
For the /12/6/7.png
- Folder: 12
- Subfolder: 6
- 7.png
Feel free to ask for more details if something is not clear.
来源：https://stackoverflow.com/questions/31880610/how-to-store-image-tiles-in-file-system-for-leaflet-js