[Geoserver-users] Buffer parameter in WMS Getmap request

Jakob_Ventin · September 26, 2013, 9:22am

Hello all,

we have a need to add a buffer parameter to our WMS getmap requests.

In Geoserver docs
(http://docs.geoserver.org/latest/en/user/services/wms/vendor.html#buffer)
this is explained. Somehow i cannot get this working.

Can anyone open up what the parameter 'buffer' actually does, how it is
thought to be used and the correct syntax. Is there a maximum value for the
buffer?

What we want to achieve is uncut labels over tile boarders. As for now, we
are using a (quite big) buffer and metatiles in Getmap requests sent from
our cache service. We hope that buffering could be done in Geoserver. This
would decrease the actual amount of data being transferred.

Best regards,

Jakob

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Andrea_Aime4 · September 26, 2013, 9:32am

On Thu, Sep 26, 2013 at 11:22 AM, Jakob Ventin <jventin@anonymised.com> wrote:

Hello all,

we have a need to add a buffer parameter to our WMS getmap requests.

In Geoserver docs
(http://docs.geoserver.org/latest/en/user/services/wms/vendor.html#buffer)
this is explained. Somehow i cannot get this working.

Can anyone open up what the parameter 'buffer' actually does, how it is
thought to be used and the correct syntax. Is there a maximum value for the
buffer?

What we want to achieve is uncut labels over tile boarders. As for now, we
are using a (quite big) buffer and metatiles in Getmap requests sent from
our cache service. We hope that buffering could be done in Geoserver. This
would decrease the actual amount of data being transferred.

What you are looking for is a "gutter", not a buffer.
The buffer parameter grows the area that is being queried on the data
source,
not the one of the painted map, won't help in your case.

The best way to reduce data transfer is to use the internal GWC, no data
transfer
at all, tiles are painted and sliced in memory and written on disk directly
without
any intermediate png file generation.

Cheers
Andrea

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Jakob_Ventin · October 1, 2013, 10:15am

Thanks for the answer, now i understand.

If I understand right, it is not possible to define a gutter in a WMS GetMap
request?

-Jakob

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Simone_Giannecchini3 · October 11, 2013, 10:16am

Dear Jakob,
found this email in my drafts, hitting send now

Long answer is no, although it would be quite straightforward to add
support for the gutter parameter to GeoServer.
I would at least open up a jira to track this request for enhancement.

Regards,
Simone Giannecchini

Our support, Your Success! Visit http://opensdi.geo-solutions.it for
more information.

Ing. Simone Giannecchini
@simogeo
Founder/Director

GeoSolutions S.A.S.
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 1660272
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