Thank you,
I'll try with mod_python.
Another small question - is there any notable speed difference between
using tilecache (let's say through mod_python) to serve some pre-cached
tiles and using OpenLayers.Layer.Tilecache to serve the same pre-cached
tiles?
I'm thinking if I should pre-cache my whole map and use Layer.Tilecache
or if I can get away by using tilecache.py...
Has anyone done any benchmarks for these methods? If the speed
difference isn't that great, I wouldn't sacrifice the disk space...
Thank you.
Christopher Schmidt wrote:
On Tue, Oct 20, 2009 at 09:43:35AM +0300, Adrian Popa wrote:
Hello Christopher,
Thanks for your reply.
I am using cgi mode (because it's been the easiest to setup). How do
you recommend I run tilecache? I don't want to precache my whole map
because most of the zoom levels (in some areas) don't give much
information. I could precache some zoom levels and let the details be
rendered on the fly, when needed...
Okay, using CGI is the problem. You can only get about 10 tiles/second
with CGI, compared to hundreds with WSGI, mod_python, etc. So I recommend
setting up mod_python or some other persistant server side process for
serving the tiles, rathere than using CGI, which is much slower.
I'm not using metatiles (or at least I think I'm not using them)... I
don't really know what metatiles are and what they are supposed to do.
Maybe a point to the right documentation would be ok...
The tile loading process goes like this - when I change my zoom the
center tiles are loaded pretty quickly (even if they haven't been
cached) - in about half a second, but the edges of my image take about
~5 seconds to load. I thought it might be a limitation of my browser -
on how many connections it can keep - so I added a lot of connections
(20 per server) both on my browser and my web server (20 processes
listening). The speed limitation is visible even when the tiles (for
that area) have been cached. I thought that by increasing the tile size
the browser would make fewer requests and the page would maybe load
faster...
Thanks,
Adrian
Christopher Schmidt wrote:
On Mon, Oct 19, 2009 at 02:30:44PM +0300, Adrian Popa wrote:
Hello everyone,
Just wondering - what would be a good tile size to be used for
tilecache, so that the client will not do a lot of queries to the
server (seems they take quite a while), and at the same time would
not load too much information that is not used (areas of tiles which
are outside the viewable area).
My web clients use screen resolutions starting from 1200x1024 (and
usually run the page in full screen).
Right now I have tiles of 256x256 - which seem rather small and take
some time to load.
I would try to understand why they take some time to load. Are you using
CGI mode? (Don't.) Are you not-precaching as much as you should? Are you
using metatiles? Are you not using metatiles? etc.
Also, some description of 'some time' -- hundreds of milliseconds, seconds,
dozens of seconds -- would probably also be appropriate.
What tile sizes do you use?
256x256. And so does Google Maps, which was doing this before most of us,
and probably has a decent idea on how to make things work pretty well.
-- Chris
Thanks,
Adrian
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