[Geoserver-users] Always return blank image on getMap requests?

GeoServer GeoServer User
1

Hi,

Rather unusual use case for WMS really. Some ideas:

  • Add a huge white opaque watermark

  • Make a layer group with white layer on the top

  • Use security and deny GetMaps but allow GetFeatureInfo

-Jukka Rahkonen-

···

Lähettäjä: Casper Børgesen (CABO) [mailto:CABO@anonymised.com]
Lähetetty: 10. elokuuta 2016 14:58
Vastaanottaja: geoserver-users@lists.sourceforge.net
Aihe: [Geoserver-users] Always return blank image on getMap requests?

Hi

I am trying to use Geoserver to host +100GB’s of floating point raster data as a WMS layer. I would like to use the layer for getFeatureInfo lookups but I would like to just return a blank image on any getMap requests to the layer – no matter what the getMap request asks for.

I have tried to create a raster style with opacity set to 0.0, but it seems like Geoserver still fetches the data. I guess the raster style is evaluated after the requested data has been retrieved?

Can I configure a WMS layer to respond with a blank image on every getMap request?

Regards, Casper

2

Hi Jukka

I know it’s rather unusual, but I think that providing feature info on huge floating point raster dataset is a task that Geoserver is optimized to handle.

I do need however to avoid that Geoserver performs the retrieval of data, since requesting a getMap for a bounding box containing ex. 200GB data, would take close to forever to create a response. That is why I would like to skip the data retrieval and just send back a blank transparent image.

If I use security and deny getMap requests, wouldn’t the requester get an error in return? I would like a response corresponding to no-data-to-be-found-here.

Regards, Casper

···

From: Rahkonen Jukka (MML) [mailto:jukka.rahkonen@anonymised.com]
Sent: 10. august 2016 14:25
To: Casper Børgesen (CABO); geoserver-users@lists.sourceforge.net
Subject: Re: Always return blank image on getMap requests?

Hi,

Rather unusual use case for WMS really. Some ideas:

  • Add a huge white opaque watermark

  • Make a layer group with white layer on the top

  • Use security and deny GetMaps but allow GetFeatureInfo

-Jukka Rahkonen-

Lähettäjä: Casper Børgesen (CABO) [mailto:CABO@anonymised.com]
Lähetetty: 10. elokuuta 2016 14:58
Vastaanottaja: geoserver-users@lists.sourceforge.net
Aihe: [Geoserver-users] Always return blank image on getMap requests?

Hi

I am trying to use Geoserver to host +100GB’s of floating point raster data as a WMS layer. I would like to use the layer for getFeatureInfo lookups but I would like to just return a blank image on any getMap requests to the layer – no matter what the getMap request asks for.

I have tried to create a raster style with opacity set to 0.0, but it seems like Geoserver still fetches the data. I guess the raster style is evaluated after the requested data has been retrieved?

Can I configure a WMS layer to respond with a blank image on every getMap request?

Regards, Casper

3

why not just add tiles and overviews so GeoServer can open it efficiently? see http://www.slideshare.net/geosolutions/geoserver-on-steroids-foss4g-2015

Ian

···

On 10 August 2016 at 14:06, Casper Børgesen (CABO) <CABO@anonymised.com> wrote:

Hi Jukka

I know it’s rather unusual, but I think that providing feature info on huge floating point raster dataset is a task that Geoserver is optimized to handle.

I do need however to avoid that Geoserver performs the retrieval of data, since requesting a getMap for a bounding box containing ex. 200GB data, would take close to forever to create a response. That is why I would like to skip the data retrieval and just send back a blank transparent image.

If I use security and deny getMap requests, wouldn’t the requester get an error in return? I would like a response corresponding to no-data-to-be-found-here.

Regards, Casper

From: Rahkonen Jukka (MML) [mailto:jukka.rahkonen@maanmittauslaitos.fi]
Sent: 10. august 2016 14:25
To: Casper Børgesen (CABO); geoserver-users@anonymised.comsourceforge.net
Subject: Re: Always return blank image on getMap requests?

Hi,

Rather unusual use case for WMS really. Some ideas:

  • Add a huge white opaque watermark

  • Make a layer group with white layer on the top

  • Use security and deny GetMaps but allow GetFeatureInfo

-Jukka Rahkonen-

Lähettäjä: Casper Børgesen (CABO) [mailto:CABO@anonymised.com]
Lähetetty: 10. elokuuta 2016 14:58
Vastaanottaja: geoserver-users@anonymised.comsourceforge.net
Aihe: [Geoserver-users] Always return blank image on getMap requests?

Hi

I am trying to use Geoserver to host +100GB’s of floating point raster data as a WMS layer. I would like to use the layer for getFeatureInfo lookups but I would like to just return a blank image on any getMap requests to the layer – no matter what the getMap request asks for.

I have tried to create a raster style with opacity set to 0.0, but it seems like Geoserver still fetches the data. I guess the raster style is evaluated after the requested data has been retrieved?

Can I configure a WMS layer to respond with a blank image on every getMap request?

Regards, Casper

What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. http://sdm.link/zohodev2dev

Geoserver-users mailing list
Geoserver-users@anonymised.com.382…sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-users

–

Ian Turton

4

Hi Ian and Jukka

@Ian

That is a workaround that would work, but it is a lot of retiling/overviewing combined with returning the result 100% transparent just to make the getMap request fast.

@Jukka

I am trying to avoid various request parameters, &layers, &query_layers since I’m not using web gis, but rather just various desktop gis applications, where I cannot control the request parameters.

I could set up a service to filter out the requests and redirect them to the various layers, but again that is not easy to manage when adding more datasets.

Consider having a nice visualization of a floating point data set but if the user send a getFeatureInfo request they get the RGB(A) value back. In this case it would be much nicer to let the visualization respond to the getMap request and the floating point dataset respond to the getFeatureInfo request. Not a layer group but something like a “request mapper” acting as a layer.

Regards, Casper

···

why not just add tiles and overviews so GeoServer can open it efficiently? see http://www.slideshare.net/geosolutions/geoserver-on-steroids-foss4g-2015

Ian

On 10 August 2016 at 14:06, Casper Børgesen (CABO) <CABO@…4891…> wrote:

Hi Jukka

I know it’s rather unusual, but I think that providing feature info on huge floating point raster dataset is a task that Geoserver is optimized to handle.

I do need however to avoid that Geoserver performs the retrieval of data, since requesting a getMap for a bounding box containing ex. 200GB data, would take close to forever to create a response. That is why I would like to skip the data retrieval and just send back a blank transparent image.

If I use security and deny getMap requests, wouldn’t the requester get an error in return? I would like a response corresponding to no-data-to-be-found-here.

Regards, Casper

From: Rahkonen Jukka (MML) [mailto:jukka.rahkonen@…6847…]
Sent: 10. august 2016 14:25
To: Casper Børgesen (CABO); geoserver-users@lists.sourceforge.net
Subject: Re: Always return blank image on getMap requests?

Hi,

Rather unusual use case for WMS really. Some ideas:

  • Add a huge white opaque watermark

  • Make a layer group with white layer on the top

  • Use security and deny GetMaps but allow GetFeatureInfo

-Jukka Rahkonen-

Lähettäjä: Casper Børgesen (CABO) [mailto:CABO@…4864…]
Lähetetty: 10. elokuuta 2016 14:58
Vastaanottaja: geoserver-users@lists.sourceforge.net
Aihe: [Geoserver-users] Always return blank image on getMap requests?

Hi

I am trying to use Geoserver to host +100GB’s of floating point raster data as a WMS layer. I would like to use the layer for getFeatureInfo lookups but I would like to just return a blank image on any getMap requests to the layer – no matter what the getMap request asks for.

I have tried to create a raster style with opacity set to 0.0, but it seems like Geoserver still fetches the data. I guess the raster style is evaluated after the requested data has been retrieved?

Can I configure a WMS layer to respond with a blank image on every getMap request?

Regards, Casper

What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. http://sdm.link/zohodev2dev

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

–

Ian Turton

5

On 11 August 2016 at 07:16, Casper Børgesen (CABO) <CABO@anonymised.com> wrote:

Hi Ian and Jukka

@Ian

That is a workaround that would work, but it is a lot of
retiling/overviewing combined with returning the result 100% transparent
just to make the getMap request fast.

You need that optimisation to get any sort of speed out of the getinfo
request too - otherwise GeoServer is reading in 100s+GB to return one point
each and every time.

I think you may be better off looking at WCS or WPS as better ways of doing
this.

Ian

6

Hi Ian

I have setup the floating point dataset as an image mosaic, so I would expect it to use the index and then any internal tiling to make a fast getFeatureInfo lookup?

Regards, Casper

···

On 11 August 2016 at 07:16, Casper Børgesen (CABO) <CABO@…4891…> wrote:

Hi Ian and Jukka

@Ian

That is a workaround that would work, but it is a lot of retiling/overviewing combined with returning the result 100% transparent just to make the getMap request fast.

You need that optimisation to get any sort of speed out of the getinfo request too - otherwise GeoServer is reading in 100s+GB to return one point each and every time.

I think you may be better off looking at WCS or WPS as better ways of doing this.

Ian

7

Hi Ian,
that should not be the case, the raster feature info identifier is reading a 20x20 block around the clicked pixel, but at the native
resolution, not the requested one (see the code, it’s using the “original grid to world”):

https://github.com/geoserver/geoserver/blob/master/src/wms/src/main/java/org/geoserver/wms/featureinfo/RasterLayerIdentifier.java

So, if one has a mosaic, at most 4 files will be read, and if they are inner tiled, at most 4 tiles total will be read (but in the common
case, just one tile from one file)

Cheers
Andrea

···

On Thu, Aug 11, 2016 at 4:23 PM, Ian Turton <ijturton@anonymised.com> wrote:

What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. http://sdm.link/zohodev2dev

Geoserver-users mailing list
Geoserver-users@anonymised.com.382…sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-users

–

On 11 August 2016 at 07:16, Casper Børgesen (CABO) <CABO@…4891…> wrote:

Hi Ian and Jukka

@Ian

That is a workaround that would work, but it is a lot of retiling/overviewing combined with returning the result 100% transparent just to make the getMap request fast.

You need that optimisation to get any sort of speed out of the getinfo request too - otherwise GeoServer is reading in 100s+GB to return one point each and every time.

I think you may be better off looking at WCS or WPS as better ways of doing this.

Ian

==
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