[OpenLayers-Users] Accessing an Offline Tile Store

[Joaquim Muchaxo]

Hi, 

  the tiles on disk have a known layout into folders and files, so a mapping from a tile url to files is possible.
This means you would not need an http request you would open a disk file.
The correspondence from bounding box to tile folder/filename is generally given by a formula. This formula depends on the tile software you have used. 

I may help a little more for instance if you are using tilecache or geowebcache. 

If other just look it up a little on google.
I'd also suggest you ask this on 

http://gis.stackexchange.com/

 
regards,

Joaquim.


----- Original Message -----
From: Chris W <chrisw.osgeo at psychogeeks.com>
To: openlayers-users at lists.osgeo.org
Cc: 
Sent: Friday, 20 July 2012, 6:06
Subject: [OpenLayers-Users] Accessing an Offline Tile Store

Hello All,

I've been looking at the possibility of providing an offline map in a Qt
application.  The QtWebKit component would be used to host an OpenLayers
page inside the application.  As a first cut I have implemented a basic
local web server to provide XYZ tile service to an OL layer from local
mbtiles databases.  This all works, and is more disk-space and
distribution friendly than using raw tiles on the disk.  It has the
disadvantage that the desktop app requires a port (multiple ports on
terminal server machines) and exposes the tile service to external
access (localhost anyway)

I had thought of alternate approach that could eliminate the web
server.  QtWebKit offers a C++ to Javascript bridge that allows js to
make calls to C++ functions and vice versa.  If the transport for tile
requests could be replaced with js calls into the C++ the tile service
code could be subsumed into the C++ widget code and no longer be exposed
to the outside world.   Inspection of the inheritance hierarch of the
XYZ layer would seem to indicate an intimate relationship to HTTP... but
I am a bit of a js neophyte.

I wonder if the replacement of the OL transport layer for base layer
tiles retrieval is even possible?  Has something like this been done?

Regards,
Chris

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