Very well explained, thanks,
However, one problem with one layer solution is that when I am trying Q2
and Q3 it
returns also non-point nodes (edge and polygons) which are not part of the
result.
So I think it might be better for me to have two layers. Is there any
performance cost on having several layers?
Using the two layer approach for query Q2 and Q3 I am not getting the
desired results. For instance for query Q2:
Node s = dbInstance.findNode(dbLabel, "cid", Integer.parseInt(cellId));
Geometry geometry = layer.getGeometryEncoder().decodeGeometry(s);
List<SpatialDatabaseRecord> snodes = GeoPipeline.
startNearestNeighborLatLonSearch(layer, geometry.getCoordinate(),
1.0).toSpatialDatabaseRecordList();
where the coordinates of node s are (0.0, 0.0). It returns only the node
itself. Looking at the source,
it seems startNearestNeighborLatLonSearch builds a window which is much
more smaller. Should I
build my own window and pass to startNearestNeighborLatLonSearch instead of
last param ?
Similar problem with startNearestNeighborSearch when looking for K
neighbors.
Cheers,
Thanks,
Alireza
On Wednesday, August 12, 2015 at 4:36:35 PM UTC+2, Craig Taverner wrote:
>
> Hi Alireza,
>
> Since you have three different geometry types, you are correct to use WKT
> (or WKB) for the layer. This layer can handle all three types. You do not
> need a separate layer for points. The only reason I suggested making a
> points-only layer was that I thought perhaps you only stored points. But
> since you store all types, rather have a layer that can handle all.
>
> The code you have above looks fine and similar to the test code I made. So
> it should work fine. The error you had earlier looked like you had tried to
> manually create node geometries and add the nodes to the layer, instead of
> adding the geometry to the layer.
>
> One thing I find a little strange above is that you have chosen to use an
> encoder config with three fields "x:y:z". But the WKB and WKT encoders only
> understand two. The first is the geometry property name (you chose "x" to
> hold the geometry in the node), and the second is the bbox property. I
> think it a little confusing to store a whole polygon in "x" and to store
> the envelope(bbox) in "y". I'm guessing this is not what you intended to
> do? I advise you rather pass a single string with no ':' separators, like
> 'my_geom'. Better yet, leave it empty and get the default value. In fact
> you can leave off all fields but the layer name, if you use the method
> getOrCreateEditableLayer(name).
>
> Here is a section of the test code I tried, which worked, and adds a Point
> and LineString to the layer:
>
> SpatialDatabaseService db = new SpatialDatabaseService( graphDb() );
> String layerName = "myLayer";
> String geomPropertyName = "my_geom";
> EditableLayer layer = (EditableLayer) db.getOrCreateLayer( layerName,
> WKBGeometryEncoder.class,
> EditableLayerImpl.class,
> geomPropertyName );
> GeometryFactory gf = layer.getGeometryFactory();
> SpatialDatabaseRecord record = layer.add( gf.createPoint( new Coordinate(
> 15.25, 56.15 ) ) );
> LinearRing ring = gf.createLinearRing( new Coordinate[]{
> new Coordinate( 15.3, 56.2 ),
> new Coordinate( 15.4, 56.2 ),
> new Coordinate( 15.4, 56.3 ),
> new Coordinate( 15.3, 56.3 ),
> new Coordinate( 15.3, 56.2 )
> } );
> Polygon polygon = gf.createPolygon( ring, null );
> record = layer.add( polygon );
>
> You can use WKB or WKT for this layer. Note that if you created a layer
> with simply:
>
> db.getOrCreateEditableLayer( layerName );
>
> Then you get a WKB layer with default configs.
>
> Regards, Craig
>
>
> On Wed, Aug 12, 2015 at 4:01 PM, Alireza Rezaei Mahdiraji <
> [email protected] <javascript:>> wrote:
>
>>
>> Hi Craig,
>>
>> As always thanks for your nice reply.
>>
>> I understood the problem but not the solution yet. The fact is I have
>> points, lines, and polygons as geometries.
>> Four main queries which I have are as follows:
>>
>> 1- given coordinates of an arbitrary point (i.e., not a node in the
>> graph) find the polygon node which enclose it
>>
>> 2- given a point node find all other nodes which are withing distance r
>> of it.
>>
>> 3- given a point node find all k nearest neighbors point node of it
>>
>> 4- given two polygon determines if they intersect and perhaps find the
>> size of intersection
>>
>> I defined my layer as follows (I tried with WKB too):
>>
>> EditableLayer runningLayer = (EditableLayer)
>> graphDBSpatial.getOrCreateLayer(layerName,
>> WKTGeometryEncoder.class,
>> EditableLayerImpl.class,
>> "x:y:z");
>>
>> Then I create my nodes as follows:
>>
>> // point node
>> Point p = runningLayer.getGeometryFactory().createPoint(coord);
>> SpatialDatabaseRecord v = runningLayer.add(p);
>>
>> // edge node
>> LineString lineString =
>> runningLayer.getGeometryFactory().createLineString(coord);
>> SpatialDatabaseRecord e = runningLayer.add(lineString);
>>
>> // polygon node
>> Polygon poly =
>> runningLayer.getGeometryFactory().createPolygon(coordinates);
>> SpatialDatabaseRecord tc = runningLayer.add(poly);
>>
>> Based on what you said I should have a separate layer for point, right?
>> If the answer is yes, then while querying I should load two layers
>> based on which of the queries above is requested (WKT layer for queries 1
>> and 4 and Point layer for 2 and 3), is that correct ?
>>
>> Cheers,
>> Alireza
>>
>> On Monday, August 10, 2015 at 11:09:21 AM UTC+2, Craig Taverner wrote:
>>>
>>> Hi Alireza,
>>>
>>> I wrote some test code using your layer creation and neighbour search
>>> code that you pasted, and it works fine. So what I think has happened is
>>> that you have somehow added nodes with a different layer config to the same
>>> index that you are now using for WKB. Perhaps the nodes used to be points
>>> in a simple point layer, and now you changed to a WKB layer, it is no
>>> longer compatible.
>>>
>>> I can make a few suggestions:
>>>
>>> - Make sure your nodes were added using the layer.add(Geometry)
>>> method. If you used layer.add(Node) then it is your responsibility to
>>> make
>>> sure the node conforms to the same layer config that you are planning to
>>> use. For example, do not add a simple point node (with lat/lon
>>> attributes)
>>> to a WKT layer, or you are likely to create this kind of issue.
>>> - Since you are working with points, can I suggest you not use the
>>> WKB layer config, but rather use the SimplePointLayer, as created by
>>> SpatialGraphDatabase.createSimplePointLayer(name)
>>> or SpatialGraphDatabase.createSimplePointLayer(name,xProp,yProp)
>>>
>>> Regards, Craig
>>>
>>> On Sun, Aug 9, 2015 at 12:02 AM, Alireza Rezaei Mahdiraji <
>>> [email protected]> wrote:
>>>
>>>>
>>>> Let me ask you a design kind of question: the nodes in my graph could
>>>> have various geometry: point, line, or polygon.
>>>> I used the following layer definition (but I am not sure that is the
>>>> best way to do it)"
>>>>
>>>> EditableLayer runningLayer = (EditableLayer)
>>>> graphDBSpatial.getOrCreateLayer(layerName,
>>>> WKBGeometryEncoder.class,
>>>> EditableLayerImpl.class,
>>>> geomEncoderConfig);
>>>>
>>>> I appreciate if you comment on this.
>>>>
>>>> Alireza
>>>>
>>>>
>>>> On Saturday, August 8, 2015 at 11:48:24 PM UTC+2, Michael Hunger wrote:
>>>>>
>>>>> It seems you created the layer with a WKB (well known binary)
>>>>> representation config
>>>>>
>>>>> but now your location properties are not decodable as WKB because they
>>>>> are double's ?
>>>>>
>>>>> Michael
>>>>>
>>>>> Perhaps you can share a test that reproduces the issue?
>>>>>
>>>>> Am 08.08.2015 um 23:26 schrieb Alireza Rezaei Mahdiraji <
>>>>> [email protected]>:
>>>>>
>>>>>
>>>>> Here are the stacks for the two cases (very similar):
>>>>>
>>>>> Exception in thread "main" java.lang.ClassCastException:
>>>>> java.lang.Double cannot be cast to [B
>>>>> at
>>>>> org.neo4j.gis.spatial.WKBGeometryEncoder.decodeGeometry(WKBGeometryEncoder.java:41)
>>>>> at
>>>>> org.neo4j.gis.spatial.filter.SearchIntersectWindow.onEnvelopeIntersection(SearchIntersectWindow.java:48)
>>>>> at
>>>>> org.neo4j.gis.spatial.rtree.filter.AbstractSearchEnvelopeIntersection.geometryMatches(AbstractSearchEnvelopeIntersection.java:45)
>>>>> at
>>>>> org.neo4j.gis.spatial.rtree.RTreeIndex$SearchEvaluator.checkPosition(RTreeIndex.java:286)
>>>>> at
>>>>> org.neo4j.gis.spatial.rtree.RTreeIndex$SearchEvaluator.isStopNode(RTreeIndex.java:299)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.OldTraverserWrapper$Pruner.evaluate(OldTraverserWrapper.java:260)
>>>>> at
>>>>> org.neo4j.graphdb.traversal.Evaluator$AsPathEvaluator.evaluate(Evaluator.java:69)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.MultiEvaluator.evaluate(MultiEvaluator.java:62)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.MonoDirectionalTraverserIterator.evaluate(MonoDirectionalTraverserIterator.java:61)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.TraversalBranchImpl.evaluate(TraversalBranchImpl.java:125)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.TraversalBranchImpl.initialize(TraversalBranchImpl.java:130)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.TraversalBranchImpl.next(TraversalBranchImpl.java:151)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.TraversalBranchWithState.next(TraversalBranchWithState.java:32)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.StartNodeTraversalBranch.next(StartNodeTraversalBranch.java:50)
>>>>> at
>>>>> org.neo4j.graphdb.traversal.PreorderDepthFirstSelector.next(PreorderDepthFirstSelector.java:49)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.MonoDirectionalTraverserIterator.fetchNextOrNull(MonoDirectionalTraverserIterator.java:70)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.MonoDirectionalTraverserIterator.fetchNextOrNull(MonoDirectionalTraverserIterator.java:36)
>>>>> at
>>>>> org.neo4j.helpers.collection.PrefetchingIterator.peek(PrefetchingIterator.java:60)
>>>>> at
>>>>> org.neo4j.helpers.collection.PrefetchingIterator.hasNext(PrefetchingIterator.java:46)
>>>>> at
>>>>> org.neo4j.helpers.collection.PrefetchingIterator.next(PrefetchingIterator.java:75)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.OldTraverserWrapper$TraverserImpl.next(OldTraverserWrapper.java:86)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.OldTraverserWrapper$TraverserImpl.next(OldTraverserWrapper.java:47)
>>>>> at
>>>>> org.neo4j.gis.spatial.filter.SearchRecords.next(SearchRecords.java:53)
>>>>> at
>>>>> org.neo4j.gis.spatial.filter.SearchRecords.next(SearchRecords.java:29)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.GeoPipeline$1.next(GeoPipeline.java:134)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.GeoPipeline$1.next(GeoPipeline.java:126)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.impl.LastElementIterator.next(LastElementIterator.java:19)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.impl.IdentityPipe.processNextStart(IdentityPipe.java:18)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.impl.AbstractPipe.next(AbstractPipe.java:72)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.AbstractGeoPipe.processNextStart(AbstractGeoPipe.java:49)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.AbstractGeoPipe.processNextStart(AbstractGeoPipe.java:31)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.impl.AbstractPipe.next(AbstractPipe.java:72)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.impl.Pipeline.next(Pipeline.java:113)
>>>>> at
>>>>> org.neo4j.gis.spatial.pipes.GeoPipeline.toNodeList(GeoPipeline.java:1015)
>>>>>
>>>>>
>>>>> Exception in thread "main" java.lang.ClassCastException:
>>>>> java.lang.Double cannot be cast to [B
>>>>> at
>>>>> org.neo4j.gis.spatial.WKBGeometryEncoder.decodeGeometry(WKBGeometryEncoder.java:41)
>>>>> at
>>>>> org.neo4j.gis.spatial.filter.SearchIntersectWindow.onEnvelopeIntersection(SearchIntersectWindow.java:48)
>>>>> at
>>>>> org.neo4j.gis.spatial.rtree.filter.AbstractSearchEnvelopeIntersection.geometryMatches(AbstractSearchEnvelopeIntersection.java:45)
>>>>> at
>>>>> org.neo4j.gis.spatial.rtree.RTreeIndex$SearchEvaluator.checkPosition(RTreeIndex.java:286)
>>>>> at
>>>>> org.neo4j.gis.spatial.rtree.RTreeIndex$SearchEvaluator.isStopNode(RTreeIndex.java:299)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.OldTraverserWrapper$Pruner.evaluate(OldTraverserWrapper.java:260)
>>>>> at
>>>>> org.neo4j.graphdb.traversal.Evaluator$AsPathEvaluator.evaluate(Evaluator.java:69)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.MultiEvaluator.evaluate(MultiEvaluator.java:62)
>>>>> at
>>>>> org.neo4j.kernel.impl.traversal.MonoDirectionalTraverserIterator.evaluate(MonoDirectionalTraverserIterator.ja
>>>>>
>>>>> ...
>>>>
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