[mapguide-users] OGR / GEOS selection problem

Thu Jun 14 11:43:49 EDT 2007

Kenneth's patch has been submitted. Thanks Kenneth!

I removed my previous "fix" and also tested the new fix - it works.

A new dll is posted on the same location as the old one, at
http://download.osgeo.org/fdo/3.2.2-rc1/OGRProvider-3.2.2_rc1.win32.zip

Traian

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Traian
Stanev
Sent: Thursday, June 14, 2007 10:45 AM
To: MapGuide Users Mail List
Subject: RE: [mapguide-users] OGR / GEOS selection problem

If you send me the patched file, I can submit it. 

I will also disable the skewing fix at the same time.

Traian

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Kenneth,
GEOGRAF A/S
Sent: Thursday, June 14, 2007 10:38 AM
To: MapGuide Users Mail List
Subject: Re: [mapguide-users] OGR / GEOS selection problem

Ok, I fixed it for all providers, using the GDal / GEOS intersects
operation.
Update OGRFeatureReader::ReadNext(...) to:

bool OgrFeatureReader::ReadNext()
{    
    m_sprops.clear();

    if (m_poFeature)
        OGRFeature::DestroyFeature(m_poFeature);

    m_poFeature = m_poLayer->GetNextFeature();

    //Ugly hack to fix broken providers, with BBOX only testing
    OGRGeometry* spfilter = m_poLayer->GetSpatialFilter();
    if (spfilter != NULL)
        while (m_poFeature != NULL && m_poFeature->GetGeometryRef() !=
NULL && !spfilter->Intersects(m_poFeature->GetGeometryRef()))
        {
            OGRFeature::DestroyFeature(m_poFeature);
            m_poFeature = m_poLayer->GetNextFeature();
        }

    return (m_poFeature != NULL);
}

That will work for all the providers, but has a slight overhead as the
features are transfered from the datasource (eg. database) before
testing.
Fixing the OGR provider would be better, but out of the MapGuide scope.

Also, the skewing fix can now be disabled, but does no harm.

While I was testing the PostGIS provider, I got annoyed with the lack of
error messages.
You can update the code to this:

FdoConnectionState OgrConnection::Open()
{
    const wchar_t* dsw = GetProperty(PROP_NAME_DATASOURCE);
    bool readonly = _wcsnicmp(GetProperty(PROP_NAME_READONLY), L"TRUE",
4) == 0;

    W2A(dsw);

    printf ("Attempt OGR connect to %s \n", mbdsw);
    printf ("ReadOnly %d\n", (int)readonly);

    m_poDS = OGRSFDriverRegistrar::Open(mbdsw, !readonly);
    if( m_poDS == NULL )
    {
        std::string str = "Connect failed: "; 
        str.append(CPLGetLastErrorMsg());
        const char* x = str.c_str();
        A2W(x);
        throw FdoConnectionException::Create(wx);
    }

    m_connState = FdoConnectionState_Open;

    return m_connState;
}

This will give the user a slight hint about the problem (eg, bad
connectionstring, username etc.)

Regards, Kenneth, GEOGRAF A/S

Traian Stanev skrev: 

Sure, but the actual geometric operation is what matters. If it ends up
doing a BBOX, it would not be right. It needs to do Intersects.

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Kenneth,
GEOGRAF A/S
Sent: Thursday, June 14, 2007 4:15 AM
To: MapGuide Users Mail List
Subject: Re: [mapguide-users] OGR / GEOS selection problem

It should not work if you make a polygon selection.
Tooltip and Click sends a square, so the envelope of the filter should
be the same as the filter

Regards, Kenneth, GEOGRAF A/S

Traian Stanev skrev: 

Wait, from this it looks like it takes the BBOX (envelope) of the filter
and sends that to PostGIS...? That may explain things.

	-----Original Message----- 
	From: mapguide-users-bounces at lists.osgeo.org on behalf of
Kenneth, GEOGRAF A/S 
	Sent: Wed 6/13/2007 5:42 PM 
	To: MapGuide Users Mail List 
	Cc: 
	Subject: Re: [mapguide-users] OGR / GEOS selection problem

	It is actually forwarded to PostGIS:

	        OGREnvelope  sEnvelope;

	        m_poFilterGeom->getEnvelope( &sEnvelope );
	        osWHERE.Printf("WHERE %s && SetSRID('BOX3D(%.12f %.12f,
%.12f %.12f)'::box3d,%d) ",
	                       pszGeomColumn,
	                       sEnvelope.MinX, sEnvelope.MinY,
	                       sEnvelope.MaxX, sEnvelope.MaxY,
	                       nSRSId );

	Not too good with PostGIS syntax, but since the m_poFilterGeom
is the filter used (a small square in this case) it reads:
	"Select from geometry_column where features are within the bbox
of the filer"

	Which should be quite ok, unless they have a similar idea of
optimizing this to a BBOX test, as OGR does.

	Anyway, I can confirm that Traians fix works with MapInfo TAB
files, but NOT with PostGIS :(

	Regards, Kenneth, GEOGRAF A/S

	Traian Stanev skrev: 

	To put test data into PostGres I use the tool that comes with it
that
	can import SHP files into the database.

	I think it's called shp2pgsql.

	Traian

	-----Original Message-----
	From: mapguide-users-bounces at lists.osgeo.org
	[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of
Kenneth,
	GEOGRAF A/S
	Sent: Wednesday, June 13, 2007 3:21 PM
	To: MapGuide Users Mail List
	Subject: Re: [mapguide-users] OGR / GEOS selection problem

	I tried it with MapInfo TAB files, and it works fine.

	Maciej, can you post an SQL dump of one of the PostGIS tables?

	I have installed PostGIS on my machine for testing, but I have
no data, 
	and no luck getting Fdo2Fdo working with FDO OGR.

	Regards, Kenneth, GEOGRAF A/S

	Traian Stanev skrev:

		Well, I only tried it with SHP files and am pretty sure
it fixed the
		problem for SHP files (I did a before and after test, on
a polygon

	that

		had the same problem as your screenshot). May be the
PostGIS OGR

	driver

		does something else, like forward the spatial filter to
PostGIS? In

	that

		case, may be I need to upgrade my PostGIS SDK...?
Anybody know the
		answer to that one?

		Traian

		-----Original Message-----
		From: mapguide-users-bounces at lists.osgeo.org
		[mailto:mapguide-users-bounces at lists.osgeo.org] On
Behalf Of Maciej
		Skorczewski
		Sent: Wednesday, June 13, 2007 12:29 PM
		To: MapGuide Users Mail List
		Subject: Re: [mapguide-users] OGR / GEOS selection
problem

		Traian

		i have still this same error...

		take a look on screen.

		http://imagepolis.com/images/20070613819095046.JPG

		http://imagepolis.com/images/20070613818181055.JPG

		http://imagepolis.com/images/20070613434408347.JPG

		Maciek

		ps. and i still can't use SetSelectionXML...

http://www.nabble.com/SetSelectionXML-on-layer-from-database-%28PostgreS

		QL-%3EPostgGIS%29-tf3900386s16610.html

		(tiny of this url to forum)
		http://tiny.pl/fdtn

		maciek skorczewski

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