[mapserver-users] Re: QGis 'Zoom to best scale' Not Working

[Travis Kirstine]

Are you requesting the "MyGroup" layer or "MyImage", I'm not sure if
the group inherits the layer metadata (I'm sure someone on the list
knows).  I have noticed that when adding grouped layers in QGIS the
zoom to extent does not work however it will work when individual
layers are added.

Regards

On 22 November 2011 06:08, SixDegrees <paulcarlisle at comcast.net> wrote:
> Sorry, I was wrong in the previous message; the resx and resy settings do
> show up in the capabilities document. They make no difference, however; the
> bounding box requested by QGis is still in error.
>
>
> SixDegrees wrote
>>
>> Thank you. I added wms_resx and wms_resy to my mapfile with reasonable
>> values (and some unreasonable ones, just as tests). This makes no
>> difference. When I make a GetCapabilities request, the layer's bounding
>> box is correct but it does NOT contain the resx or resy settings, as I
>> believe it should.
>>
>> I don't know if this is a problem in my mapfile or in MapServer. My
>> mapfile layer looks like this (file names changed for proprietary
>> reasons):
>>
>> LAYER
>>    NAME "MyImage"
>>    GROUP "MyGroup"
>>    EXTENT 75.80425 35.304 76.01625 35.476
>>    METADATA
>>       "wms_title" "MyImage"
>>       "wms_group_title" "MyGroup"
>>       "wms_extent" "75.80425 35.304 76.01625 35.476"
>>       "wms_srs" "EPSG:4326"
>>       "wms_resx" "1.0" # Note: these values are for testing only. The
>> actual values have
>>       "wms_resy" "1.0" # also been tried, with no success. They are
>> 5.90139233796e-06, -4.85244300668e-06
>>    END
>>    PROCESSING "SCALE=AUTO"
>>    PROCESSING "SCALE_BUCKETS=256"
>>    TYPE RASTER
>>    DATA "MyImage.vrt"
>>    PROJECTION
>>       "+proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs"
>>    END
>> END
>>
>>
>>
>>
>> Rahkonen Jukka wrote
>>>
>>> Hi,
>>>
>>> WMS does not advertise by default the native resolution of the data.  I
>>> have never tried but perhaps adding wms_resx, wms_resy metadata into
>>> layer metadata would add that information into GetCapabilities
>>> http://mapserver.org/ogc/wms_server.html.
>>>  I do not know if QGis can utilise that information even if it exists.
>>>
>>> -Jukka Rahkonen-
>>>
>>> SixDegrees wrote:
>>>
>>>> I'm not sure if this is a QGis problem or a problem with my
>>> Mapserver-generated WMS layer. When I load a WMS image in QGis,
>>> everything
>>> works as expected except when I select 'Zoom to best scale' I get a
>>> Mapserver error stating that the bounding box is illegal. And it is - the
>>> bounding box corner points in the getmap request are identical. This
>>> selections is supposed to zoom in so the pixels displayed are 1:1 or 100%
>>>
>>>> A look at the capabilities request returned by Mapserver and the mapfile
>>>> and
>>> images involved don't show anything obviously wrong. Is it possible that
>>> QGis is sending the wrong request? Or is something missing from either
>>> the
>>> capabilities document or the mapfile layer?
>>>
>>>> I'm not really sure where to start looking to isolate the problem. Note
>>>> that
>>> if I load images directly instead of through Mapserver WMS I am able to
>>> zoom
>>> to scale without any problem, which suggests a problem with Mapserver,
>>> likely in the mapfile. I am using VRT files as intermediaries between the
>>> Mapfile and the underlying NITF files; it seems that Mapserver should be
>>> using the affine transform contained in the VRT to determine proper
>>> scaling,
>>> but I'm not sure if that is sufficient. Are there arguments that need to
>>> be
>>> placed in the Mapfile metadata to help WMS generation along? Or something
>>> that would cause items in the capabilities document to be left out?
>>>
>>>> Using QGis 1.7.0 on Linux.
>>>
>>> --
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>>
>
>
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