Thanks Jackie,
I pasted this comment into the ticket - perhaps comment in there to keep a
public thread and for anyone searching in future:
OK, so though I was expecting something like the query below I hadn't realised
in the WFS specification
>> 7.9.2.5.2 KVP encoding
>> For KVP-encoded requests the selection clause shall be encoded using
>> one of the keywords
>> FILTER, RESOURCEID or BBOX (see ISO 19143, Table 2).
So it is *NOT* possible to combine a BBOX with a FILTER
I guess my comment now is that this implementation of restrictToBBox (without
an RFC) has effectively created a different FDO provider that had different
capabilities. The WFS provider publishes it's capabilities as
ExpressionType_Basic with ConditionType_Comparison as well as
ConditionType_Spatial.
However, when the restrictToBBox=True the ONLY ConditionType is Spatial. The
problem is that the capabilities are at the provider level and not at the
connection string and so applications (like commercial AutoCAD Map) and others
will present a WFS interface that allows property queries to be created but
these will never be executed - resulting in a user experience of different
resultsset than specified/expected.
{{{
http://ogc.bgs.ac.uk/digmap625k_gsml_insp_gs/wfs?version=2.0.0
&service=WFS
&REQUEST=GetFeature&service=WFS
&TYPENAMES=gsmlp:GBR_BGS_625k_BA_INSP&REQUEST=GetFeature
&BBOX=200000.0,600000.0,300000.0,700000.0,urn:ogc:def:crs:EPSG::27700&TYPENAMES=gsmlp:GBR_BGS_625k_BA_INSP
&SRSNAME=urn:ogc:def:crs:EPSG::27700
&Filter=<Filter xmlns="http://www.opengis.net/ogc";
xmlns:gml="http://www.opengis.net/gml";
xmlns:gsmlp="http://xmlns.geosciml.org/geosciml-portrayal/4.0";><PropertyIsEqualTo><PropertyName>lithology</PropertyName><Literal>Basalt</Literal></PropertyIsEqualTo></Filter>
}}}
Best regards,
Crispin
________________________________
From: mapguide-users <[email protected]> on behalf of
Jackie Ng via mapguide-users <[email protected]>
Sent: Tuesday, July 15, 2025 11:21 AM
To: MapGuide Users Mail List <[email protected]>
Subject: Re: [mapguide-users] WFS FDO Ignores Filter When RestrictToBBox is True
I had some time to look at the issue in question and if we trace back to the
original commit message in https://trac.osgeo.org/fdo/changeset/8194
WFS Provider: Some WFS servers support BBOX filter only, but don't support
normal filter. Some other servers support normal filter only, but don't support
BBOX filter. In order to handle the 2 kinds of WFS servers, we add a new
configuration item RestrictToBBox. If it is true, FDO WFS provider will
generate BBOX filter for queries. Otherwise, it will generate normal filter as
before
Based on my interpretation of that commit message, I believe this would be
intentional behavior. This setting seems to only be enabled to handle a
specific kind of WFS server which if your example WFS server is producing the
correct results when this setting is false then perhaps it's just a case of not
turning on this setting?
- Jackie
On Thu, 10 Jul 2025 at 21:14, Jackie Ng wrote:
Hi Crispin,
Thanks for the bug report.
I'm somewhat busy this week, so I'll take a look at this early next week.
- Jackie
You wrote:
Hi,
I documented this more at https://trac.osgeo.org/fdo/ticket/1009 but think that
is fairly unmonitored and as it obviously affects MGOS4 I hope it can get some
attention as affecting MapGuide issue.
As MGS is by it's nature as a web mapping viewer, it applies a BBox /
Intersects query for every web map page request.
The issue is that if the new format RestrictToBBox = True is applied to the WFS
query connection parameters then all property/aspatial filters are
stripped/ignored when sent to the WFS server; resulting in an unexpected return
of ALL data within the map window.
See sample MGP package attached, based on open British Geological Survey data.
The attached screen grab shows the WebLayout preview highlighting in red Basalt
lithography (use the WebLayout as it zooms/centres to a sensible scale and
area). The initial display used the connection format WITHOUT the BBox
parameter.
If the other Filtered themed layer is turned on, even though it has a filter
for lithology='Basalt', all data is returned.
It is the BBox parameter that results in unexpected results, even though filter
and BBox are possible.
See FDO ticket for details or use Fiddler etc and apply proxy parameters to the
WFS connection to capture web traffc.
Best regards,
Crispin
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