[mapguide-users] SetSpatialFilter and MgFeatureSpatialOperations problem with search

[Kenneth Skovhede, GEOGRAF A/S]

Hi Maciej.

I have seen cases where the first record of the datasource is returned 
no matter what the query is.
You are likely seeing a different problem, but now you know :).

In the pretty picture you have drawn, the lower part shows the parcel 
(with the number three), which
clearly touches the yellow parcel. AFAIK, there is no direct spatial 
operation that allows you to
select only the grey one. You can however calculate the area of which 
the two polygons overlap,
and filter out the yellow, based on overlapped area. You can choose to 
discard polygon with
a very smal overlapping area, or only select the one with the largest 
overlapping area.

Is there a problem with only selecting parcels that intersect the actual 
point the user clicked on?

If you are actually using the point, you are likely using the OGR 
provider, and having this problem:
http://trac.osgeo.org/fdo/ticket/343

Regards, Kenneth Skovhede, GEOGRAF A/S



Maciej Skorczewski skrev:
> Hi
>
> my problem is with "SetSpatialFilter" , in my application user click 
> on PARCEL (on map) , and after click on "get REGION name" application 
> should try to search in which REGION (biger surface) is the PARCEL.
>
>
> what i want to get is:
>
> help image :)
> http://img171.imageshack.us/img171/8450/51030812fq1.png
>
> so when user click on small parcel (in grey REGION), first pictures he 
> should get ID of big grey REGION.
>
> i you see on second image if parcel is nearly yellow REGION user 
> should  get ID ONLY  grey  region ....
>
>
> I try use all method like:
>
> MgFeatureSpatialOperations::Intersects
>
> it is work but i get all REGION who Intersects my parcel (yellow and 
> grey  region ), after try another MgFeatureSpatialOperations like:
>
> MgFeatureSpatialOperations::Contains = 0
> MgFeatureSpatialOperations::CoveredBy = 8
> MgFeatureSpatialOperations::Crosses = 1
> MgFeatureSpatialOperations::Disjoint = 2
> MgFeatureSpatialOperations::EnvelopeIntersects = 10
> MgFeatureSpatialOperations::Equals = 3
> MgFeatureSpatialOperations::Inside = 9
> MgFeatureSpatialOperations::Intersects = 4
> MgFeatureSpatialOperations::Overlaps = 5
> MgFeatureSpatialOperations::Touches = 6
> MgFeatureSpatialOperations::Within = 7
>
>
> but get wrong/or none results
>
> That is may procedure
> 1. user click on map
> 2. he press button "REGION info"
> 3. application use Getselection method to get selected parcel info: 
> ID,NAME, and x,y Coordinates
> 4. I create new polygon (Coordinates come from selected parcel)
> 5. i use SetSpatialFilter and by iteration on all map layer i  check
> what layer is in selected polygon range (REGION).
>
>
>
> //------------my code
> $selectedFeatures2=array(); //REGION ID,NAME etc.
> //$coords -- come from selected parcel (GetCoordinates())
>
> //generate new polygon from selected parcel
> $linearRing = $geometryFactory->CreateLinearRing($coords);
> $parcel_polygon = $geometryFactory->CreatePolygon($linearRing, null);
> $resourceService=$siteConnection->CreateService(MgServiceType::ResourceService); 
>
>
>
> ///--------BEGIN layer iteration...on all map layer
>
>
> $layer = $map->GetLayers()->GetItem($layer_name[$i]);
> $resId = new MgResourceIdentifier($layer->GetFeatureSourceId());
> $featureGeometry = $layer->GetFeatureGeometryName();
> $featureClass = $layer->GetFeatureClassName();
> $schemaAndClass = explode(":", $featureClass);
> $featureService 
> =$siteConnection->CreateService(MgServiceType::FeatureService);
> $queryOptions = new MgFeatureQueryOptions();
> $queryOptions->SetSpatialFilter($featureGeometry,
> $polygon,MgFeatureSpatialOperations::Intersects);
>
>
> $featureReader = $featureService->SelectFeatures($resId, 
> $layer->GetFeatureClassName(), $queryOptions);
>                 while ($featureReader->ReadNext())
>                 { 
> $selectedFeatures2[]=array("layer_name"=>$featureReader->GetString('Layer'),"FeatureId"=>$featureReader->GetInt32('FeatureId')); 
>
>                 }
>
>
>
> ///--------END layer iteration...on all map layer
>
>
>
>
>
>
>
>
> Can you pleas give me some sample code for this?
>
>
>
>
>
> macieksk
> _______________________________________________
> mapguide-users mailing list
> mapguide-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/mapguide-users