[Geoserver-devel] R: R: Planning the next few months (warning, long mail)

GeoServer GeoServer Developer
1

Wow!

Thank you guys for the fast and insightful answers, another point scored for the Open Source communities!

If I understand well, Andrea is working on implementing some mechanism directly into GeoServer which will improve tiled rendering (I didn't know about versioned data store, I'll read all the docs I can get as soon as possible). And this maybe in genuary, right?

In the meantime one can use tilecache, Chris says. I tried the demo, and I still noticed some cell cut. Is is because of the 5x5 tile mechanism of TileCache? If it is so, does that mean TileCache "saves" many cell, but not all? Apart from this, TileCache seems interesting for performance reason too, so if I'll be able to install and use it effectively, I'll be happy to write down the steps I will have followed, if you think that would be useful for others.

Anyway, thank you again for your precious support, and Happy New Year!

Cheers,

Fabio

-----Messaggio originale-----
Da: Chris Holmes [mailto:cholmes@anonymised.com]
Inviato: venerdì 29 dicembre 2006 18.26
A: Fabio Da Soghe
Cc: 'Geoserver-devel'
Oggetto: Re: [Geoserver-devel] R: Planning the next few months (warning, long mail)

We're hoping to work on it relatively soon, at the very least the fix to
do better rendering of labels for tiles.

But in the meantime, if you're using metacarta's TileCache -
http://labs.metacarta.com/wms-c/ - they have an option called 'metaTile'
that gives pretty nice results with regards to tiles on GeoServer.

See: http://sigma.openplans.org/ for an example and
http://sigma.openplans.org/tilecache-1.3/tilecache.cfg for how we set up
the params (note that you need version 1.3 and the python imaging
library for it to work properly).

What it does is request a 5x5 tile (which you can set to be even bigger
with the metaSize param) from the WMS, and cuts it up on the client
side. This is how ka-map works actually, as MapServer's renderer is
even more finicky for tiles than GeoServer (they also need the
metaBuffer so lines don't get rounded off). Some labeling is still
repeated, but it's not at every tile so it looks much better.

You also get better performance overall - the first tile will come back
a bit more slowly, but the set of tiles will come much more quickly, as
GeoServer does better rendering a large area all at once. And of course
that's only on areas that haven't been pre-cached. You can use their
client to pre-cache you're whole map if it's not too big. (I need to
take some time to write up a nice tutorial on setting all this up...)

If that's not sufficient for you and you're interested in funding the
patch to the renderer immediately or getting directions on how to do it
yourself let us know.

best regards,

Chris

Fabio Da Soghe wrote:

Hello list.

I'm reading this thread with much interest. In the webmapping application my company is building (based on GeoServer), we're sadly discovering the issue about tiled rendering (label moving near tile boundary and cell and text cutting).

Tiled rendering is very "cool" and definitively a must for us (for both performance and usability reasons), but these problem seems to put a stop on this road.

Directly supporting it in GeoServer (via WMS-C or TMS) would be great, but in the meantime we're guessing if there could be some workaround that let one use the tile mechanism and still keep getting correct maps (without at least ugly cut cells).

Has anybody some hint in this direction? Maybe through a patch to GeoServer, as was discussed in this list some time ago (about a possible vendor-specific option in the SLD with which to get no cross-tile label, for example)?

Many thanks in advance for any feedback.

Best Regards,

Fabio Da Soghe

-----Messaggio originale-----
Da: geoserver-devel-bounces@lists.sourceforge.net [mailto:geoserver-devel-bounces@lists.sourceforge.net] Per conto di Andrea Aime
Inviato: lunedì 11 dicembre 2006 9.00
A: Paul Ramsey
Cc: Geoserver-devel
Oggetto: Re: [Geoserver-devel] Planning the next few months (warning, long mail)

Paul Ramsey ha scritto:

On 10-Dec-06, at 8:55 AM, Andrea Aime wrote:

* tiled WMS: this requires changes in both the gt2 renderer and
    a new module that builds on top on the current WMS I guess.
    Changes required in the renderer are not earth shattering, so
    I guess they could be handled in 2.3.x or 2.4.x once branched.

Why do you perceive tiling as a re-implementation issue? I think the
TileCache approach already being pushed by Metacarta shows that it's
just a layering on top of existing rendering infrastructures. So WMS
tiling should be handled as another layer on top of an (unchanged)
render stack?

Yes, you could, and it can be work very fine.
At the minimum, we require the geotools renderer to stop moving labels for each different rendering request, and this is in the pack of "properly supporting WMS-C", that is, just fix the current WMS and make it usable to serve tiles with TileCache on top of it.

Supporting TMS in Geoserver is another matter. From where I stand, if an admin is familiar with Apache and Python he would choose MapServer or Mapnik as the backend anyways, unless he needs better looking maps.

On the contrary, an organisation using already Java may be uncomfortable of fiddling with another piece of software, one using Microsoft stuff would be probably even more scared away from having to install not one but two foreign technologies.

Having around TileCache makes it less urgent to implement one in Geoserver, at the same time the implementation is already there and quite nice and compact, so re-coding it in Geoserver should not be a major effort either.

Cheers
Andrea Aime

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Geoserver-devel mailing list
Geoserver-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-devel

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys - and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Geoserver-devel mailing list
Geoserver-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-devel

!DSPAM:1003,45954c16300391665516417!

--
Chris Holmes
The Open Planning Project
http://topp.openplans.org

2

Fabio Da Soghe ha scritto:

Wow!

Thank you guys for the fast and insightful answers, another point
scored for the Open Source communities!

If I understand well, Andrea is working on implementing some
mechanism directly into GeoServer which will improve tiled rendering
(I didn't know about versioned data store, I'll read all the docs I
can get as soon as possible). And this maybe in genuary, right?

In the meantime one can use tilecache, Chris says. I tried the demo,
and I still noticed some cell cut. Is is because of the 5x5 tile
mechanism of TileCache? If it is so, does that mean TileCache "saves"
many cell, but not all? Apart from this, TileCache seems interesting
for performance reason too, so if I'll be able to install and use it
effectively, I'll be happy to write down the steps I will have
followed, if you think that would be useful for others.

Well, the assesment is mostly correct, but not fully.
Even with tilecache you'll have troubles with jumping labels.
What I want to do before end of January, is to solve the jumping
labels issue, so that Geoserver + TileCache works for real.

The rest will come later... being TileCache around we aren't
so much pressed to do things that are fully integrated in Geoserver,
thougth that would mean easier deploy and better performance.

Cheers
Andrea

3

Fabio Da Soghe ha scritto:

Wow!

Thank you guys for the fast and insightful answers, another point scored for the Open Source communities!

Ciao Fabio,
tanto per curiosità, posso chiedere come state usando Geoserver
e come vi trovate? Che applicazione state sviluppando?
Non ci sono pericoli di fuga di notizie, lavoro direttamente per
OpenPlans :-p

Ciao
Andrea

4

In the meantime one can use tilecache, Chris says. I tried the demo, and I still noticed some cell cut. Is is because of the 5x5 tile mechanism of TileCache? If it is so, does that mean TileCache "saves" many cell, but not all? Apart from this, TileCache seems interesting for

Not all of that map was cached with metaTile, so you may just be looking at areas that didn't get it. I cleared the top 8 zooms or so and redid those, and everything new is with metaTile, but some aren't. But it's also not perfect, just a lot better. You could try playing with bigger metaSize's and buffers, ect.

Also note that you'll get really good performance if you did it with mod_python. We haven't even done that yet, but it's supposed to be a lot faster.

No need for you to write it up, it's on my todo list. But when I write it up if you could review it that would be great, see if I missed everything.

best regards,

Chris

Anyway, thank you again for your precious support, and Happy New Year!

Cheers,

Fabio

-----Messaggio originale-----
Da: Chris Holmes [mailto:cholmes@anonymised.com] Inviato: venerdì 29 dicembre 2006 18.26
A: Fabio Da Soghe
Cc: 'Geoserver-devel'
Oggetto: Re: [Geoserver-devel] R: Planning the next few months (warning, long mail)

We're hoping to work on it relatively soon, at the very least the fix to do better rendering of labels for tiles.

But in the meantime, if you're using metacarta's TileCache - http://labs.metacarta.com/wms-c/ - they have an option called 'metaTile' that gives pretty nice results with regards to tiles on GeoServer.

See: http://sigma.openplans.org/ for an example and http://sigma.openplans.org/tilecache\-1\.3/tilecache\.cfg for how we set up the params (note that you need version 1.3 and the python imaging library for it to work properly).

What it does is request a 5x5 tile (which you can set to be even bigger with the metaSize param) from the WMS, and cuts it up on the client side. This is how ka-map works actually, as MapServer's renderer is even more finicky for tiles than GeoServer (they also need the metaBuffer so lines don't get rounded off). Some labeling is still repeated, but it's not at every tile so it looks much better.

You also get better performance overall - the first tile will come back a bit more slowly, but the set of tiles will come much more quickly, as GeoServer does better rendering a large area all at once. And of course that's only on areas that haven't been pre-cached. You can use their client to pre-cache you're whole map if it's not too big. (I need to take some time to write up a nice tutorial on setting all this up...)

If that's not sufficient for you and you're interested in funding the patch to the renderer immediately or getting directions on how to do it yourself let us know.

best regards,

Chris

Fabio Da Soghe wrote:

Hello list.

I'm reading this thread with much interest. In the webmapping application my company is building (based on GeoServer), we're sadly discovering the issue about tiled rendering (label moving near tile boundary and cell and text cutting).

Tiled rendering is very "cool" and definitively a must for us (for both performance and usability reasons), but these problem seems to put a stop on this road.

Directly supporting it in GeoServer (via WMS-C or TMS) would be great, but in the meantime we're guessing if there could be some workaround that let one use the tile mechanism and still keep getting correct maps (without at least ugly cut cells).

Has anybody some hint in this direction? Maybe through a patch to GeoServer, as was discussed in this list some time ago (about a possible vendor-specific option in the SLD with which to get no cross-tile label, for example)?

Many thanks in advance for any feedback.

Best Regards,

Fabio Da Soghe

-----Messaggio originale-----
Da: geoserver-devel-bounces@lists.sourceforge.net [mailto:geoserver-devel-bounces@lists.sourceforge.net] Per conto di Andrea Aime
Inviato: lunedì 11 dicembre 2006 9.00
A: Paul Ramsey
Cc: Geoserver-devel
Oggetto: Re: [Geoserver-devel] Planning the next few months (warning, long mail)

Paul Ramsey ha scritto:

On 10-Dec-06, at 8:55 AM, Andrea Aime wrote:

* tiled WMS: this requires changes in both the gt2 renderer and
    a new module that builds on top on the current WMS I guess.
    Changes required in the renderer are not earth shattering, so
    I guess they could be handled in 2.3.x or 2.4.x once branched.

Why do you perceive tiling as a re-implementation issue? I think the TileCache approach already being pushed by Metacarta shows that it's just a layering on top of existing rendering infrastructures. So WMS tiling should be handled as another layer on top of an (unchanged) render stack?

Yes, you could, and it can be work very fine.
At the minimum, we require the geotools renderer to stop moving labels for each different rendering request, and this is in the pack of "properly supporting WMS-C", that is, just fix the current WMS and make it usable to serve tiles with TileCache on top of it.

Supporting TMS in Geoserver is another matter. From where I stand, if an admin is familiar with Apache and Python he would choose MapServer or Mapnik as the backend anyways, unless he needs better looking maps.

On the contrary, an organisation using already Java may be uncomfortable of fiddling with another piece of software, one using Microsoft stuff would be probably even more scared away from having to install not one but two foreign technologies.

Having around TileCache makes it less urgent to implement one in Geoserver, at the same time the implementation is already there and quite nice and compact, so re-coding it in Geoserver should not be a major effort either.

Cheers
Andrea Aime

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Geoserver-devel mailing list
Geoserver-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-devel

-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys - and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Geoserver-devel mailing list
Geoserver-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-devel

--
Chris Holmes
The Open Planning Project
http://topp.openplans.org