NearestNeighbor and GeoWebCache producing bad quality tiles

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NearestNeighbor and GeoWebCache producing bad quality tiles

GeoServer - User mailing list
Have setup GeoServer to work with GeoWebCache. Apparently, I have applied
most of the tweaks for improving performance and quality, but still have
rendering issues when using Nearest Neighbor interpolation or GeoWebCache:

Summarizing, I have:

 - Enabled direct integration with GeoServer WMS, tiled=true..etc
 - Enabled the fullWMS mode, using hints=quality parameter in the URL

I have been using Bicubic interpolation because this produces good results
for basemaps when viewed as WMS. This is what I get when using WMS+Bicubic:
<http://osgeo-org.1560.x6.nabble.com/file/t385047/good_result.png>

However, when using Nearest Neighbor+WMS, a white line pattern shows up. So
lines and labels seem to be "split". This is only a slight change but it
makes the map pretty much unreadable:
<http://osgeo-org.1560.x6.nabble.com/file/t385047/rendering_issue.png>

Now, when moving to GeoWebCache with Bicubic interpolation, I expected to
get the same good results as Bicubic+WMS. However, it turns out that I have
exactly the same rendering issue when using GeoWebCache.

My guess is that I am doing something wrong in the layer setup that
generates the rendering issue both in NearestNeighbor+WMS and
GeoWebCache+whatever interpolation method used.

If possible, I would like to use NearestNeighbor because it requires less
resources. I think that if I can get the rendering issue with
NearestNeighbor sorted, then the results will be good in GeoWebCache as
well. BTW, the rendering issue happens also when using Bilinear method.

Can anybody provide some feedback on what I'm doing wrong with this basemap?



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Re: NearestNeighbor and GeoWebCache producing bad quality tiles

geowolf
Hi,
the fullWMS mode is something that is not used much, if at all, for a number of reasons:
  • last I checked, it could not be setup via the GUI (so hard to find for many)
  • reading PNG tiles and re-assembling them is not particularly fast, it's convenient only if the original map is pretty slow (un-optimized raster, very complex vector map)
  • the rendering quality is poor, suitable mostly for resampling raster data, but blurs lines and labels in a normally unacceptable way
In my company we simply never use it, I remember trying it and getting "foggy" results, but not disconnected lines as you did.
Just mind, the results of bilinear interpolation, even when the white line disconnection is fixed, are not going to be the same as a
WMS rendering with bilinear, if you dataset is vector the interpolation settings are not used at all, vectors are scaled to the targer
resolution before being drawn on the canvas.

I'd suggest you setup a small, reproducible test case, and submit it to https://osgeo-org.atlassian.net/projects/GEOS/summary
If this has any urgency for you, I'd also check out commercial support options at http://geoserver.org/support/

Cheers
Andrea

On Wed, Jun 12, 2019 at 3:24 PM Maik1 via Geoserver-users <[hidden email]> wrote:
Have setup GeoServer to work with GeoWebCache. Apparently, I have applied
most of the tweaks for improving performance and quality, but still have
rendering issues when using Nearest Neighbor interpolation or GeoWebCache:

Summarizing, I have:

 - Enabled direct integration with GeoServer WMS, tiled=true..etc
 - Enabled the fullWMS mode, using hints=quality parameter in the URL

I have been using Bicubic interpolation because this produces good results
for basemaps when viewed as WMS. This is what I get when using WMS+Bicubic:
<http://osgeo-org.1560.x6.nabble.com/file/t385047/good_result.png>

However, when using Nearest Neighbor+WMS, a white line pattern shows up. So
lines and labels seem to be "split". This is only a slight change but it
makes the map pretty much unreadable:
<http://osgeo-org.1560.x6.nabble.com/file/t385047/rendering_issue.png>

Now, when moving to GeoWebCache with Bicubic interpolation, I expected to
get the same good results as Bicubic+WMS. However, it turns out that I have
exactly the same rendering issue when using GeoWebCache.

My guess is that I am doing something wrong in the layer setup that
generates the rendering issue both in NearestNeighbor+WMS and
GeoWebCache+whatever interpolation method used.

If possible, I would like to use NearestNeighbor because it requires less
resources. I think that if I can get the rendering issue with
NearestNeighbor sorted, then the results will be good in GeoWebCache as
well. BTW, the rendering issue happens also when using Bilinear method.

Can anybody provide some feedback on what I'm doing wrong with this basemap?



--
Sent from: http://osgeo-org.1560.x6.nabble.com/GeoServer-User-f3786390.html


_______________________________________________
Geoserver-users mailing list

Please make sure you read the following two resources before posting to this list:
- Earning your support instead of buying it, but Ian Turton: http://www.ianturton.com/talks/foss4g.html#/
- The GeoServer user list posting guidelines: http://geoserver.org/comm/userlist-guidelines.html

If you want to request a feature or an improvement, also see this: https://github.com/geoserver/geoserver/wiki/Successfully-requesting-and-integrating-new-features-and-improvements-in-GeoServer


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Regards, Andrea Aime == GeoServer Professional Services from the experts! Visit http://goo.gl/it488V for more information. == Ing. Andrea Aime @geowolf Technical Lead GeoSolutions S.A.S. Via di Montramito 3/A 55054 Massarosa (LU) phone: +39 0584 962313 fax: +39 0584 1660272 mob: +39 339 8844549 http://www.geo-solutions.it http://twitter.com/geosolutions_it ------------------------------------------------------- Con riferimento alla normativa sul trattamento dei dati personali (Reg. UE 2016/679 - Regolamento generale sulla protezione dei dati “GDPR”), si precisa che ogni circostanza inerente alla presente email (il suo contenuto, gli eventuali allegati, etc.) è un dato la cui conoscenza è riservata al/i solo/i destinatario/i indicati dallo scrivente. Se il messaggio Le è giunto per errore, è tenuta/o a cancellarlo, ogni altra operazione è illecita. Le sarei comunque grato se potesse darmene notizia. This email is intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential or otherwise protected from disclosure. We remind that - as provided by European Regulation 2016/679 “GDPR” - copying, dissemination or use of this e-mail or the information herein by anyone other than the intended recipient is prohibited. If you have received this email by mistake, please notify us immediately by telephone or e-mail.



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Please make sure you read the following two resources before posting to this list:
- Earning your support instead of buying it, but Ian Turton: http://www.ianturton.com/talks/foss4g.html#/
- The GeoServer user list posting guidelines: http://geoserver.org/comm/userlist-guidelines.html

If you want to request a feature or an improvement, also see this: https://github.com/geoserver/geoserver/wiki/Successfully-requesting-and-integrating-new-features-and-improvements-in-GeoServer


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Re: NearestNeighbor and GeoWebCache producing bad quality tiles

GeoServer - User mailing list
Hi Andrea, thanks for your answer. It turns out I determined that the problem
was entirely coming from the NearestNeighbor rendering method. GeoWebCache
has nothing to do with this.

Are there any modifications that can be made in terms keep using
NearestNeighbor while keeping a good image quality?





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_______________________________________________
Geoserver-users mailing list

Please make sure you read the following two resources before posting to this list:
- Earning your support instead of buying it, but Ian Turton: http://www.ianturton.com/talks/foss4g.html#/
- The GeoServer user list posting guidelines: http://geoserver.org/comm/userlist-guidelines.html

If you want to request a feature or an improvement, also see this: https://github.com/geoserver/geoserver/wiki/Successfully-requesting-and-integrating-new-features-and-improvements-in-GeoServer


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