[Geoserver-devel] Two new extensions: "gwc-vendor" and "centroid"

GeoServer GeoServer Developer
1

Hey all,

I’ve written two new extensions and would like to add them as community modules. Is there somebody who could approve (or reject) these?

  1. gwc-vendor: This is an extension to the GeoWebCache integration to always pass through supported WMS vendor parameters (currently supports “env” and “styles”). This is handy when the requested SLD (“styles”) and values for SLD variable substitution (“env”) are variable, but still need to be cache.

    Currently I am using this for a layer in which specific features need to be highlighted (i.e., “styles=highlight&env=featureToHighlight:myFeature”). This is similar to the second technique described at http://trac.osgeo.org/openlayers/wiki/Highlighting. While this generates a large number of tiles, I still need the generated tiles to be cached. I imagine others will have similar use cases.

  2. centroid: This extension adds a new WFS GetFeature output format, “json-centroid”. Instead of returning full geometry data, json-centroid only returns the center point of each feature. This prevents large and complex geometries from being returned when they are not needed.

    As an example, I have an OpenLayers map that makes GetFeature requests when the user clicks on the map. This extension ensures that the response is not overly large. It also has the advantage of not requiring simplified geometry to be precalculated.

I’d be happy to answer any further questions. Thanks.

Rohan Singh

2

On Fri, Nov 11, 2011 at 1:18 AM, Rohan Singh <rohan@anonymised.com> wrote:

Hey all,

I’ve written two new extensions and would like to add them as community modules. Is there somebody who could approve (or reject) these?

  1. gwc-vendor: This is an extension to the GeoWebCache integration to always pass through supported WMS vendor parameters (currently supports “env” and “styles”). This is handy when the requested SLD (“styles”) and values for SLD variable substitution (“env”) are variable, but still need to be cache.

    Currently I am using this for a layer in which specific features need to be highlighted (i.e., “styles=highlight&env=featureToHighlight:myFeature”). This is similar to the second technique described at http://trac.osgeo.org/openlayers/wiki/Highlighting. While this generates a large number of tiles, I still need the generated tiles to be cached. I imagine others will have similar use cases.

Hum, this one might be nice to just integrate into the official module? Not sure if there are any unforeseen side effects, would be good to see the sources.

  2. centroid: This extension adds a new WFS GetFeature output format, “json-centroid”. Instead of returning full geometry data, json-centroid only returns the center point of each feature. This prevents large and complex geometries from being returned when they are not needed.

    As an example, I have an OpenLayers map that makes GetFeature requests when the user clicks on the map. This extension ensures that the response is not overly large. It also has the advantage of not requiring simplified geometry to be precalculated.

This one might get obsolete soon. What you are doing there is processing, which is in the realm of WPS.
The WPS extension could trivially do what you want above if someone writes a centroid process (should be quick).
Right now using the WPS extension is not so safe in that it comes with a mix of quick and heavy processes,
but we should get the ability to cherry pick what processes to expose rather soon.
I guess the only downside left at that point would be that WPS is a different protocol.

Anyways, don’t take any of these as a rejection, just as a discussion.
If you want to contribute those as community modules you have my +1 of course, just exploring alternative
approaches to integrate your work.

Cheers
Andrea

–

Ing. Andrea Aime
GeoSolutions S.A.S.
Tech lead

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3

Hello Rohan,

wrt to the extra parameterFilters for gwc layers, it would be good if
you can provide a patch instead. I'll be glad to review and integrate,
although perhaps not exactly as you made it since the ability to
configure extra parameter filters on a per layer basis is to come. I'm
currently working on GWC configuration through the UI (gridsets and
integrated layers), and as well as we can cache multiple styles now,
there will be the possibility to cache based on orther parameters
(especially time and elevation, but it should be generic enough as to
allow you to configure any of them).

So yeah, I'll be glad to take a look at a patch and if it seems easy
enough maybe integrate it before we have this full UI configuration in
place. Perhaps as just checkboxes to "cache env" as well as styles
(which is currently supported as a global setting in the gwc config
page).

Cheers,
Gabriel

On Thu, Nov 10, 2011 at 9:18 PM, Rohan Singh <rohan@anonymised.com> wrote:

Hey all,

I've written two new extensions and would like to add them as community
modules. Is there somebody who could approve (or reject) these?

gwc-vendor: This is an extension to the GeoWebCache integration to always
pass through supported WMS vendor parameters (currently supports "env" and
"styles"). This is handy when the requested SLD ("styles") and values for
SLD variable substitution ("env") are variable, but still need to be cache.

Currently I am using this for a layer in which specific features need to be
highlighted (i.e., "styles=highlight&env=featureToHighlight:myFeature").
This is similar to the second technique described at
http://trac.osgeo.org/openlayers/wiki/Highlighting. While this generates a
large number of tiles, I still need the generated tiles to be cached. I
imagine others will have similar use cases.

centroid: This extension adds a new WFS GetFeature output format,
"json-centroid". Instead of returning full geometry data, json-centroid only
returns the center point of each feature. This prevents large and complex
geometries from being returned when they are not needed.

As an example, I have an OpenLayers map that makes GetFeature requests when
the user clicks on the map. This extension ensures that the response is not
overly large. It also has the advantage of not requiring simplified geometry
to be precalculated.

I'd be happy to answer any further questions. Thanks.
--
Rohan Singh
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4

Thanks for the feedback, Andrea and Gabriel.

I agree that that the gwc-vendor extension would be better as a patch. I’ll try rewriting it this weekend as patch, and just add a simple checkbox on the GWC configuration UI to enable/disable it.

As for the centroid extension, it looks like WPS extension is exactly what I was looking for! I’m going to redo this extension as a WPS process.

On Fri, Nov 11, 2011 at 4:34 AM, Gabriel Roldan <groldan@anonymised.com> wrote:

Hello Rohan,

wrt to the extra parameterFilters for gwc layers, it would be good if
you can provide a patch instead. I’ll be glad to review and integrate,
although perhaps not exactly as you made it since the ability to
configure extra parameter filters on a per layer basis is to come. I’m
currently working on GWC configuration through the UI (gridsets and
integrated layers), and as well as we can cache multiple styles now,
there will be the possibility to cache based on orther parameters
(especially time and elevation, but it should be generic enough as to
allow you to configure any of them).

So yeah, I’ll be glad to take a look at a patch and if it seems easy
enough maybe integrate it before we have this full UI configuration in
place. Perhaps as just checkboxes to “cache env” as well as styles
(which is currently supported as a global setting in the gwc config
page).

Cheers,
Gabriel

On Thu, Nov 10, 2011 at 9:18 PM, Rohan Singh <rohan@anonymised.com> wrote:

Hey all,

I’ve written two new extensions and would like to add them as community
modules. Is there somebody who could approve (or reject) these?

gwc-vendor: This is an extension to the GeoWebCache integration to always
pass through supported WMS vendor parameters (currently supports “env” and
“styles”). This is handy when the requested SLD (“styles”) and values for
SLD variable substitution (“env”) are variable, but still need to be cache.

Currently I am using this for a layer in which specific features need to be
highlighted (i.e., “styles=highlight&env=featureToHighlight:myFeature”).
This is similar to the second technique described at
http://trac.osgeo.org/openlayers/wiki/Highlighting. While this generates a
large number of tiles, I still need the generated tiles to be cached. I
imagine others will have similar use cases.

centroid: This extension adds a new WFS GetFeature output format,
“json-centroid”. Instead of returning full geometry data, json-centroid only
returns the center point of each feature. This prevents large and complex
geometries from being returned when they are not needed.

As an example, I have an OpenLayers map that makes GetFeature requests when
the user clicks on the map. This extension ensures that the response is not
overly large. It also has the advantage of not requiring simplified geometry
to be precalculated.

I’d be happy to answer any further questions. Thanks.

Rohan Singh

RSA(R) Conference 2012
Save $700 by Nov 18
Register now
http://p.sf.net/sfu/rsa-sfdev2dev1

Geoserver-devel mailing list
Geoserver-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-devel

–
Gabriel Roldan
OpenGeo - http://opengeo.org
Expert service straight from the developers.