[mapguide-users] intersection with two polygones

[saloua wakrim]

hi all developpers! i draw polygones in map on layer wich named "
champs_reels" (as my code shows it), i want to draw intersection betwen
these polygones and polygones of another layer wich named "batiments" (as my
code shows), i want drw a polygones wich constitute difference between both
of these polygones (on layers" champs_reels" and "batiments"), this my code
when i compile it it gives me this error:
A geometry exception occurred.
"TopologyException: side location conflict (893583,107815)", if some one has
any idea please tell it me, thanks a lot in advance: what's wrong???


Dim query As MgFeatureQueryOptions = New MgFeatureQueryOptions()

query.SetFilter("ID<>0")

Dim clalque_vue_cam As MgLayer = map.GetLayers().GetItem("champs_reels")

Dim featureReader As MgFeatureReader = clalque_vue_cam.SelectFeatures(query)

While featureReader.ReadNext()

Dim geometrypoly As MgByteReader = featureReader.GetGeometry(
"BufferGeometry")

Dim geometryReaderWriter As MgAgfReaderWriter = New MgAgfReaderWriter()

Dim poly As MgPolygon = geometryReaderWriter.Read(geometrypoly)

polygones.Add(poly)



End While

Dim propertyValues As MgPropertyCollection = New MgPropertyCollection()

Dim coordcol As MgCoordinateCollection = New MgCoordinateCollection()

Dim query2 As MgFeatureQueryOptions = New MgFeatureQueryOptions()

query2.SetFilter("FeatId<>0")

Dim batiments As MgLayer = map.GetLayers().GetItem("batiments")

Dim featureReader2 As MgFeatureReader = batiments.SelectFeatures(query2)



While featureReader2.ReadNext()



Dim geometrybati As MgByteReader = featureReader2.GetGeometry("Geometry")

Dim geometryReaderWriter2 As MgAgfReaderWriter = New MgAgfReaderWriter()

Dim batiment As MgPolygon = geometryReaderWriter2.Read(geometrybati)

'listbatiments.Add(batiment)

' If polygones(i).Touches(batiment) Then

Dim polyintersection As MgPolygon = polygones(i).Difference(batiment)

'Dim cord As MgCoordinateIterator = polyintersection.GetCoordinates()



'While cord.MoveNext()

'Dim cordonees As MgCoordinate = cord.GetCurrent()

'coordcol.Add(cordonees)

'Dim outring As MgLinearRing = geomfactory.CreateLinearRing(coordcol)

'Dim poly As MgPolygon = geomfactory.CreatePolygon(outring, Nothing)

propertyValues.Add(New MgGeometryProperty("BufferGeometry",
NewMgAgfReaderWriter().Write(polyintersection )))

Dim insert As MgInsertFeatures = New MgInsertFeatures(
"BufferLayerSchema2:BufferClass2", propertyValues)



Dim commands As MgFeatureCommandCollection = NewMgFeatureCommandCollection()

commands.Add(insert)



feature.UpdateFeatures(bufferFeatureResId2, commands, False)

End While
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