Freezing when zooming into WMS with scroll wheel

[qgib]

Author Name: David McDermott (David McDermott)
Original Redmine Issue: 14615
Affected QGIS version: 2.14.0
Redmine category:web_services_clients/wms

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Good day QGIS'ers,

I have been having trouble with using the scroll wheel to zoom into WMS layer. This is only a problem when trying to zoom in two or more zoom factors at once. It doesn't produce a minidump, it just freezes meaning to you have to force quit. This is not a problem with other web plugins like QuickMapService and OpenLayers.

Thanks,

[qgib]

Author Name: Giovanni Manghi (@gioman)

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Please provide a WMS server URL and layer/s name/s.

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• category_id was configured as Web Services clients/WMS
• status_id was changed from Open to Feedback

[qgib]

Author Name: David McDermott (David McDermott)

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Hi Giovanni,

Here are two different WMS feeds that produce the same problem:

http://environment.data.gov.uk/ds/wms?SERVICE=WMS&INTERFACE=ENVIRONMENT--6f51a299-351f-4e30-a5a3-2511da9688f7&request=GetCapabilities

http://t0.ads.astuntechnology.com/open/osopen/service?REQUEST=GetCapabilities

[qgib]

Author Name: Giovanni Manghi (@gioman)

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do they work as expected on QGIS 2.8.* ?

[qgib]

Author Name: Jukka Rahkonen (Jukka Rahkonen)

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I would first check if each wheel click creates a new GetMap request. If it does it may freeze the WMS server. Right thing to do is to wait a while and listen if the wheel is still scrolled. I am remembering that about 0.2 seconds wait was implemented into OpenJUMP.

[qgib]

Author Name: David McDermott (David McDermott)

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Thank you for your responses. I investigated further using Fiddler to look at the web traffic. I found that a 407 error appears shortly before it froze. After speaking with my IT department they placed me outside the proxy and I disabled the settings in QGIS and the problem seems to have disappeared. I don't know anything about how this stuff works but my thinking is that the WMS server was unable to authenticate the request before receiving the next one which caused it to time out.

The removal of the proxy worked for me but it not a solution for all the users in our organisation who cannot be outside the proxy. Therefore, is this a problem for the WMS provider or QGIS? Can QGIS cache the GetMap requests and decelerate them.

Thanks.

[qgib]

Author Name: Giovanni Manghi (@gioman)

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The removal of the proxy worked for me but it not a solution for all the users in our organisation who cannot be outside the proxy. Therefore, is this a problem for the WMS provider or QGIS? Can QGIS cache the GetMap requests and decelerate them.

I don't think that the is any QGSI bug in this case. It maybe be improved for this specific situations, but this is best suited for a feature request.

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• resolution was changed from to invalid
• status_id was changed from Feedback to Closed