Actually, Andreas Wilhelm is working right now on updating geometries.
Sent from my phone. On Jul 2, 2011 5:00 PM, "Boris Kizelshteyn" <[email protected]> wrote: > Wow that's great! I'll try it out asap. This leads to my next question: how > do I update the geometry in a layer, rather than add new? What I am thinking > of doing is having a multipoint geometery associated with each of my user > nodes which will represent their location history. My plan is to add the > geometry to a "world" layer and then associate the returned node with the > user. How do I then add new points to that connecter node? Can I just edit > the wkt and assume the index will update? Or do you have a better suggestion > for doing this? I would rather avoid having each point be a seperate node as > I am tracking gps data and getting lots of coordinates, it would be many > thousands of nodes per user. > > Many thanks! > >> >> >> On Sat, Jul 2, 2011 at 6:48 AM, Craig Taverner <[email protected]> wrote: >> >>> Hi Boris, >>> >>> Ah! You are using the REST API. That changes a lot, since Neo4j Spatial is >>> only recently exposed in REST and we do not expose most of the >>> capabilities >>> I have discussed in this thread, or indeed in my other answer today. >>> >>> I did recently add some REST methods that might work for you, specifically >>> the addEditableLayer, which makes a WKB layer, and the >>> addGeometryWKTToLayer, for adding any kind of Geometry (including >>> LineString) to the layer. However, these were only added recently, and I >>> have no experience using them myself, so consider this very much prototype >>> code. From your other question today, can I assume you are having trouble >>> making sense of the data coming back? So we need a better way to return >>> the >>> results in WKT instead of WKB? One option would be to enhance the >>> addEditableLayer method to allow the creation of WKT layers instead of WKB >>> layers, so the internal representation is more internet friendly. >>> >>> I've just added untested support for setting the format to WKT for the >>> internal representation of the editable layer in the REST interface. This >>> is >>> untested (outside of my usual unit tests, that is), and is only in the >>> trunk >>> of neo4j-spatial, but you are welcome to try it out and see what happens. >>> >>> Regards, Craig >>> >>> On Fri, Jul 1, 2011 at 5:29 PM, Boris Kizelshteyn <[email protected]> >>> wrote: >>> >>> > Hi Craig, >>> > >>> > Thanks so much for this reply. It is very insightful. Is it possible for >>> me >>> > to implement the LineString geometries and lookups using REST? >>> > >>> > Many thanks! >>> > >>> > On Wed, Jun 8, 2011 at 4:58 PM, Craig Taverner <[email protected]> >>> wrote: >>> > >>> > > OK. I understand much better what you want now. >>> > > >>> > > Your person nodes are not geographic objects, they are persons that >>> can >>> > be >>> > > at many positions and indeed move around. However, the 'path' that >>> they >>> > > take >>> > > is a geographic object and can be placed on the map and analysed >>> > > geographically. >>> > > >>> > > So the question I have is how do you store the path the person takes? >>> Is >>> > > this a bunch of position nodes connected back to that person? Or >>> perhaps >>> > a >>> > > chain of position-(next)->position-(next)->position, etc? However you >>> > have >>> > > stored this in the graph, you can express this as a geographic object >>> by >>> > > implementing the GeometryEncoder interface. See, for example, the 6 >>> lines >>> > > of >>> > > code it takes to traverse a chain of NEXT locations and produce a >>> > > LineString >>> > > geometry in the SimpleGraphEncoder at >>> > > >>> > > >>> > >>> https://github.com/neo4j/neo4j-spatial/blob/master/src/main/java/org/neo4j/gis/spatial/encoders/SimpleGraphEncoder.java#L82 >>> > > >>> > > < >>> > > >>> > >>> https://github.com/neo4j/neo4j-spatial/blob/master/src/main/java/org/neo4j/gis/spatial/encoders/SimpleGraphEncoder.java#L82 >>> > > >If >>> > > you do this, you can create a layer that uses your own geometry >>> encoder >>> > (or >>> > > the SimpleGraphEncoder I referenced above, if you use the same graph >>> > > structure) and your own domain model will be expressed as LineString >>> > > geometries and you can perform spatial operations on them. >>> > > >>> > > Alternatively, if your data is more static in nature, and you are >>> > analysing >>> > > only what the person did in the past, and the graph will therefor not >>> > > change, perhaps you do not care to store the locations in the graph, >>> and >>> > > you >>> > > can just import them as a LineString directly into a standard layer. >>> > > >>> > > Whatever route you take, the final action you want to perform is to >>> find >>> > > points near the LineString (path the person took). I do not think the >>> > > bounding box is the right approach for that either. You need to try, >>> for >>> > > example, the method findClosestEdges in the utilities class at >>> > > >>> > > >>> > >>> https://github.com/neo4j/neo4j-spatial/blob/master/src/main/java/org/neo4j/gis/spatial/SpatialTopologyUtils.java#L115 >>> > > >>> > > < >>> > > >>> > >>> https://github.com/neo4j/neo4j-spatial/blob/master/src/main/java/org/neo4j/gis/spatial/SpatialTopologyUtils.java#L115 >>> > > >This >>> > > method can find the part of the persons path that it closest to the >>> point >>> > > of >>> > > interest. There also also many other geographic operations you might >>> be >>> > > interested in trying, once you have a better feel for the types of >>> > queries >>> > > you want to ask. >>> > > >>> > > Regards, Craig >>> > > >>> > > On Wed, Jun 8, 2011 at 2:17 AM, Boris Kizelshteyn <[email protected]> >>> > > wrote: >>> > > >>> > > > Thanks for the detailed response! Here is what I'm trying to do and >>> I'm >>> > > > still not sure how to accomplish it: >>> > > > >>> > > > 1. I have a node which is a person >>> > > > >>> > > > 2. I have geo data as that person moves around the world >>> > > > >>> > > > 3. I use the geodata to create a bounding box of where that person >>> has >>> > > been >>> > > > today >>> > > > >>> > > > 4. I want to say, was this person A near location X today? >>> > > > >>> > > > 5. I do this by seeing if location X is in A's bounding box. >>> > > > >>> > > > From looking at what you suggest doing, it's not clear how I assign >>> the >>> > > > node >>> > > > person A to a layer? Is it that the bounding box is now in the layer >>> > and >>> > > > not >>> > > > in the node? The issue then becomes, how od I associate the two as >>> the >>> > > > RTree >>> > > > relationship seems to establish itself on the bounding box between >>> the >>> > > node >>> > > > and the layer. >>> > > > >>> > > > Many thanks for your patience as I learn this challenging material. >>> > > > >>> > > > On Tue, Jun 7, 2011 at 4:13 PM, Craig Taverner <[email protected]> >>> > wrote: >>> > > > >>> > > > > I think you need to differentiate the bounding boxes of the data >>> in >>> > the >>> > > > > layer (stored in the database), and the bounding box of the search >>> > > query. >>> > > > > The search query is not stored in the database, and will not be >>> seen >>> > as >>> > > a >>> > > > > node or nodes in the database. So if you want to search for data >>> > within >>> > > > > some >>> > > > > bounding box or polygon, then express that in the search query, >>> and >>> > you >>> > > > do >>> > > > > not need to care about how your nodes are stored in the database. >>> > > > > >>> > > > > So when you say you want to make a larger bounding box, I assume >>> you >>> > > are >>> > > > > talking about the query itself. The REST API has the method >>> > > > > findGeometriesInLayer, which takes minx, maxx, miny, maxy >>> parameters >>> > > and >>> > > > > you >>> > > > > can set those to whatever you want for your query. >>> > > > > >>> > > > > The REST API also exposes the CQL query language supported by >>> > GeoTools. >>> > > > > This >>> > > > > allows you to perform SQL-like queries on geometries and feature >>> > > > > attributes. >>> > > > > For example, you can search for all objects within a specific >>> polygon >>> > > > (not >>> > > > > just a rectangular bounding box), as well as conforming to certain >>> > > > > attributes. See >>> > > > > >>> > > > >>> > > >>> > >>> http://docs.geoserver.org/latest/en/user/tutorials/cql/cql_tutorial.htmlfor >>> > > > > some examples of CQL. >>> > > > > >>> > > > > However, our current CQL support is not fully integrated with the >>> > RTree >>> > > > > index. This means that the CQL itself will not benefit from the >>> > index, >>> > > > but >>> > > > > be a raw search. You can, however, still get the benefit of the >>> index >>> > > by >>> > > > > passing in the bounding box separately. So, for example, you want >>> to >>> > > > search >>> > > > > for data in a polygon. Make the polygon object, get it's bounding >>> box >>> > > and >>> > > > > also the CQL query string. Then make a 'dynamic layer' using the >>> CQL >>> > > > (which >>> > > > > is a bit like making a prepared statement). Then perform the same >>> > > > > 'findGeometriesInLayer' method mentioned above, using the bounding >>> > box >>> > > > and >>> > > > > the dynamic layer (containing the CQL). This has the effect of >>> using >>> > > the >>> > > > > RTree index for a first approximate search, followed by pure CQL >>> for >>> > > the >>> > > > > final mile. >>> > > > > >>> > > > > See examples of this in action in the Unit tests in the source >>> code. >>> > > > > >>> > > > > >>> > > > >>> > > >>> > >>> https://github.com/neo4j/neo4j-spatial/blob/master/src/test/java/org/neo4j/gis/spatial/ServerPluginTest.java#L109 >>> > > > > has >>> > > > > examples of CQL queries on the REST API. >>> > > > > >>> > > > > On Tue, Jun 7, 2011 at 5:48 PM, Boris Kizelshteyn < >>> [email protected]> >>> > > > > wrote: >>> > > > > >>> > > > > > Thanks! So it seems you are saying that the bounding box >>> represents >>> > a >>> > > > > > single >>> > > > > > point and is the same as the lat/lat lon? What if I make the >>> > bounding >>> > > > box >>> > > > > > bigger? What I am trying to do is geo queries against a bounding >>> > box >>> > > > made >>> > > > > > of >>> > > > > > a set of points, rather than individual points. So the query is, >>> > find >>> > > > the >>> > > > > > nodes where the given point falls inside their bounding boxes. >>> Can >>> > I >>> > > do >>> > > > > > this >>> > > > > > with REST? >>> > > > > > >>> > > > > > Thanks! >>> > > > > > >>> > > > > > On Tue, Jun 7, 2011 at 11:34 AM, Craig Taverner < >>> [email protected]> >>> > > > > wrote: >>> > > > > > >>> > > > > > > Hi, >>> > > > > > > >>> > > > > > > The bounding boxes are used by the RTree index, which is a >>> > typical >>> > > > way >>> > > > > to >>> > > > > > > index spatial data. For Point data, the lat/long and the >>> bounding >>> > > box >>> > > > > are >>> > > > > > > the same thing, but for other shapes (streets/LineString and >>> > > > Polygons), >>> > > > > > the >>> > > > > > > bounding box is quite different to the actual geometry (which >>> is >>> > > not >>> > > > > just >>> > > > > > a >>> > > > > > > single lat/long, but a set of connected points forming a >>> complex >>> > > > > shape). >>> > > > > > > >>> > > > > > > The RTree does not differentiate between points and other >>> > > geometries, >>> > > > > > > because it cares only about the bounding box, and therefor we >>> > > provide >>> > > > > > that >>> > > > > > > even for something as simple as a Point. >>> > > > > > > >>> > > > > > > Does that answer the question? >>> > > > > > > >>> > > > > > > Regards, Craig >>> > > > > > > >>> > > > > > > On Tue, Jun 7, 2011 at 4:57 PM, Boris Kizelshteyn < >>> > > [email protected]> >>> > > > > > > wrote: >>> > > > > > > >>> > > > > > > > Greetings! >>> > > > > > > > >>> > > > > > > > Perhaps someone using neo4j-spatial can answer this >>> seemingly >>> > > > simple >>> > > > > > > > question. Nodes classified into layers have both lat/lon >>> > > properties >>> > > > > and >>> > > > > > > > bounding boxes, the bounding box seems to be required to >>> > > establish >>> > > > > the >>> > > > > > > > relationship between node and layer, however the node is not >>> > > found >>> > > > if >>> > > > > > the >>> > > > > > > > lat/lon does not match the query. Can someone explain the >>> > > > > relationship >>> > > > > > > > between these two properties on a node? >>> > > > > > > > >>> > > > > > > > Many thanks! >>> > > > > > > > _______________________________________________ >>> > > > > > > > Neo4j mailing list >>> > > > > > > > [email protected] >>> > > > > > > > https://lists.neo4j.org/mailman/listinfo/user >>> > > > > > > > >>> > > > > > > _______________________________________________ >>> > > > > > > Neo4j mailing list >>> > > > > > > [email protected] >>> > > > > > > https://lists.neo4j.org/mailman/listinfo/user >>> > > > > > > >>> > > > > > _______________________________________________ >>> > > > > > Neo4j mailing list >>> > > > > > [email protected] >>> > > > > > https://lists.neo4j.org/mailman/listinfo/user >>> > > > > > >>> > > > > _______________________________________________ >>> > > > > Neo4j mailing list >>> > > > > [email protected] >>> > > > > >>> > > > > >>> > > > _______________________________________________ >>> > > > Neo4j mailing list >>> > > > [email protected] >>> > > > https://lists.neo4j.org/mailman/listinfo/user >>> > > > >>> > > _______________________________________________ >>> > > Neo4j mailing list >>> > > [email protected] >>> > > https://lists.neo4j.org/mailman/listinfo/user >>> > > >>> > _______________________________________________ >>> > Neo4j mailing list >>> > [email protected] >>> > https://lists.neo4j.org/mailman/listinfo/user >>> > >>> _______________________________________________ >>> Neo4j mailing list >>> [email protected] >>> https://lists.neo4j.org/mailman/listinfo/user >>> >> > _______________________________________________ > Neo4j mailing list > [email protected] > https://lists.neo4j.org/mailman/listinfo/user _______________________________________________ Neo4j mailing list [email protected] https://lists.neo4j.org/mailman/listinfo/user
