[OpenLayers-Users] Accessing an Offline Tile Store
Chris W
chrisw.osgeo at psychogeeks.com
Thu Jul 19 22:06:07 PDT 2012
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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