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I am facing this problem 3th day and I really don't know where is the problem, so please help me.

Here is my REQUEST: http://geoportal.cuzk.cz/WMS_SM5V_PUB/service.svc/get?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&LAYERS=SM_STP_HRBITOV&STYLES=&CRS=EPSG%3A102067&BBOX=-895000,-865000,-623000,-620000&WIDTH=1600&HEIGHT=610&FORMAT=image/png&

Here is Capabilities file: http://geoportal.cuzk.cz/WMS_SM5V_PUB/WMService.aspx?service=WMS&request=GetCapabilities&

Can somebody please explain me why blank map is returned?

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    Is the request trying to view the map at a scale beyond their Max Scale of 1:6500? If trying to view the layer outside of that range, it may be blank. You may need to adjust the BBOX and Width/Height to get a map at the required scale. – SaultDon Mar 6 '13 at 17:44
  • How can I figure out, if the request is beyond Max Scale? Can you explain me relation between Denominators and BBOX, if there is some? I couldn't find any. – exeq Mar 6 '13 at 17:51
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    The formula to calculate your scale is: scale=[(width of map in pixels*254)/(resolution in dpi, usually 96)]/Width of area requested in meters – Devdatta Tengshe Mar 7 '13 at 3:48
  • I know the scale, it's specified in Capabilites file. I really think, that problem is in combination between BBOX, HEIGHT and WIDTH parameters, like SaultDon wrote. I just can't figure how to set them. I can't find any relation between them. I think only way is to find it in official WMS specification, but it is complicately written. If somebody help me to resolve it I will be grateful – exeq Mar 7 '13 at 14:57
  • I figure, that solution is to determine scale of BBOX parameters and after check whether this scale fit between Max and MinScaleDenominator for particular layer. But I can't still find solution how to calculate scale from BBOX parameters. Here is link, where it should be explained, but it's not clear to me: stackoverflow.com/questions/9255834/… – exeq Mar 12 '13 at 13:11
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SM_STP_HRBITOV is part of a group layer called Symboly_typu_pozemku. You can view the layer on its own, but as it appears there aren't many of this type of symbol in the map, you might want to check your query with the group layer...

Layers in this group are scale dependent

...
<MaxScaleDenominator>
6500
</MaxScaleDenominator>
...

Which roughly equates to 1:6500 in a GIS client. I have the group layer showing in QGIS at 1:6700 for example.

Looking at your query using the group layer instead also returns a blank image, so whilst it is possible that the reason your query returns a blank image is that there are no such layer features in the region you have selected, it is more likely that your query is too big ~ attempts to pull back an image at a smaller scale than that supported by the symbology layer.

Some examples of requests that work are:

symbology layer

SM_STP_HRBITOV layer

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