Repository files navigation

Neo4j Spatial is a library facilitating the import, storage and querying of spatial data intheNeo4j open source graph database.

This project's manual is deployed to theNeo4j Labs page.

Since version 5.19.0, the versioning of Neo4j Spatial is aligned with the versioning of Neo4j itself.This means that Neo4j Spatial 5.19.0 is build against Neo4j 5.19, and so on.

1. Copy the desired neo4j-spatial-server-plugin-x.x.x-with-dependencies.jar from therelease page to your neo4j plugin directory.

2. set up your database with the following configuration in yourneo4j.conf file:

   dbms.security.procedures.unrestricted=spatial.*

   NOTE: If you're concerned about the security risks of unrestricted access, we recommend reviewing the code to assessthe level of risk for your use case. For example, the methodIndexAccessMode.withIndexCreate grants indexcreation capabilities within the security model. This allows users without index creation privileges to generate therequired spatial support indexes. This behavior was not intentionally designed to bypass security but was necessarydue to Neo4j’s security model, where procedures with WRITE mode are not permitted to create indexes.As a result, this adjustment was required even in the Community Edition of Neo4j.

3. Restart your Neo4j server.

4. RunCALL spatial.procedures in the Neo4j browser to see the available spatial procedures.

The key concepts of this library include:

• Allow the user to model geograph data in whatever way they wish, through providing an adapter (extendGeometryEncoder).Built-in encoders include:
  • WKT and WKB stored as properties of nodes
  • Simple points as properties of nodes (two doubles, or a double[] or a native Neo4jPoint)
  • OpenStreetMap with complex geometries stored as sub-graphs to reflect the original topology of the OSM model
• Multiple CoordinationReferenceSystem support using GeoTools
• Support the concept of multiple geographic layers, each with its own CRS and Index
• Include an index capable of searching for complex geometries (in-graph RTree index)
• Support import and export in a number of known formats (e.g. Shapefile and OSM)
• Embed the library and Neo4j within GIS tools like uDig and GeoServer

Some key features include:

• Utilities for importing from ESRI Shapefile as well as Open Street Map files
• Support for all the common geometry types
• An RTree index for fast searches on geometries
• Support for topology operations during the search (contains, within, intersects, covers, disjoint, etc.)
• The possibility to enable spatial operations on any graph of data, regardless of the way the spatial data is stored,as long as an adapter is provided to map from the graph to the geometries.
• Ability to split a single layer or dataset into multiple sub-layers or views with pre-configured filters
• Server Plugin for Neo4j Server 2.x and 3.x
  • REST API for creating layers and adding nodes or geometries to layers
  • IndexProvider API (2.x only) for Cypher access usingSTART node=node:geom({query})
  • Procedures (3.x only) for much more comprehensive access to spatial from Cypher

The current index is an RTree index, but it has been developed in an extensible way allowing for other indices to beadded if necessary.The spatial queries implemented are:

• Contain
• Cover
• Covered By
• Cross
• Disjoint
• Intersect
• Intersect Window
• Overlap
• Touch
• Within
• Within Distance

The simplest way to build Neo4j Spatial is by using maven. Just clone the git repository and run

mvn install

This will download all dependencies, compiled the library, run the tests and install the artifact in your localrepository.The spatial plugin will also be created in thetarget directory, and can be copied to your local server usinginstructions from theinstallation section.

The primary type that defines a collection of geometries is the Layer. A layer contains an index for querying. Inaddition, a Layer can be an EditableLayer if it is possible to add and modify geometries in the layer. The next mostimportant interface is the GeometryEncoder.

The DefaultLayer is the standard layer, making use of the WKBGeometryEncoder for storing all geometry types as byte[]properties of one node per geometry instance.

The OSMLayer is a special layer supporting Open Street Map and storing the OSM model as a single fully connected graph.The set of Geometries provided by this layer includes Points, LineStrings and Polygons, and as such cannot be exportedto Shapefile format, since that format only allows a single Geometry per layer. However, OMSLayer extends DynamicLayer,which allow it to provide any number of sub-layers, each with a specific geometry type and in addition based on an OSMtag filter. For example, you can have a layer providing all cycle paths as LineStrings, or a layer providing all lakesasPolygons. Underneath these are all still backed by the same fully connected graph, but exposed dynamically as apparentlyseparate geometry layers.

Spatial data is divided in Layers and indexed by a RTree.

GraphDatabaseServicedatabase =newGraphDatabaseFactory().newEmbeddedDatabase(storeDir);try{ShapefileImporterimporter =newShapefileImporter(database);importer.importFile("roads.shp","layer_roads");}finally {database.shutdown();}

If using the server, the same can be achieved with spatial procedures (3.x only):

CALLspatial.addWKTLayer('layer_roads','geometry')CALLspatial.importShapefileToLayer('layer_roads','roads.shp')

This is more complex because the current OSMImporter class runs in two phases, the first requiring a batch-inserter onthe database. There is ongoing work to allow for a non-batch-inserter on the entire process, and possibly when you haveread this that will already be available. Refer to the unit tests in classes TestDynamicLayers and TestOSMImport for thelatest code for importing OSM data. At the time of writing the following worked:

OSMImporterimporter =newOSMImporter("sweden");Map<String,String>config =newHashMap<String,String>();config.put("neostore.nodestore.db.mapped_memory","90M" );config.put("dump_configuration","true");config.put("use_memory_mapped_buffers","true");BatchInserterbatchInserter =BatchInserters.inserter(newFile(dir),config);importer.importFile(batchInserter,"sweden.osm",false);batchInserter.shutdown();GraphDatabaseServicedb =newGraphDatabaseFactory().newEmbeddedDatabase(dir);importer.reIndex(db,10000);db.shutdown();

GraphDatabaseServicedatabase =newGraphDatabaseFactory().newEmbeddedDatabase(storeDir);try {SpatialDatabaseServicespatialService =newSpatialDatabaseService(database);Layerlayer =spatialService.getLayer("layer_roads");SpatialIndexReaderspatialIndex =layer.getIndex();SearchsearchQuery =newSearchIntersectWindow(newEnvelope(xmin,xmax,ymin,ymax));spatialIndex.executeSearch(searchQuery);List<SpatialDatabaseRecord>results =searchQuery.getResults();}finally {database.shutdown();}

If using the server, the same can be achieved with spatial procedures (3.x only):

CALLspatial.bbox('layer_roads',{lon:15.0,lat:60.0},{lon:15.3,lat:61.0})

Or using a polygon:

WITH'POLYGON((15.3 60.2, 15.3 60.4, 15.7 60.4, 15.7 60.2, 15.3 60.2))'ASpolygonCALLspatial.intersects('layer_roads',polygon)YIELDnodeRETURNnode.nameASname

For further Java examples, refer to the test code in theLayersTest andtheTestSpatial classes.

For further Procedures examples, refer to the code intheSpatialProceduresTestclass.

IMPORTANT: Examples in this readme were originally tested with GeoServer 2.1.1.However, regular testing of new releases of Neo4j Spatial against GeoServer is not done,and so we welcome feedback on which versions are known to work, and which ones do not,and perhaps some hints as to the errors or problems encountered.

Each release of Neo4j Spatial builds against a specific version of GeoTools and should then be used in the version ofGeoServer that corresponds to that.The list of releases below starting at Neo4j 2.0.8 were built with GeoTools 9.0 for GeoServer 2.3.2,but most release for Neo4j 3.x were ported to GeoTools 14.4 for GeoServer 2.8.4.

For the port to Neo4j 4.0 we needed to upgrade GeoTools to 24.x to avoid bugs with older GeoTools in Java 11.This also required a complete re-write of the Neo4jDataStore and related classes.This has not been tested at all in any GeoTools enabled application, but could perhaps work with GeoServer 2.18.

mvn clean install

• unzip thetarget/xxxx-server-plugin.zip and the Neo4j libraries from your Neo4j download under$NEO4J_HOME/libinto$GEOSERVER_HOME/webapps/geoserver/WEB-INF/lib
• restart geoserver
• configure a new workspace
• configure a new datasource neo4j in your workspace. Point the "The directory path of the Neo4j database:" parameter tothe relative (form the GeoServer working dir) or absolute path to a Neo4j Spatial database with layers (seeNeo4j Spatial)
• in Layers, do "Add new resource" and choose your Neo4j datastore to see the existing Neo4j Spatial layers and addthem.

• check out the geoserver source

svn co https://svn.codehaus.org/geoserver/trunk geoserver-trunk

• build the source

cd geoserver-trunkmvn clean install

• check that you can run the web app asofThe GeoServer Maven build guide

cd src/web/appmvn jetty:run

• in$GEOSERVER_SOURCE/src/web/app/pom.xmlhttps://svn.codehaus.org/geoserver/trunk/src/web/app/pom.xml, add thefollowing lines under the profiles section:

<profile><id>neo4j</id><dependencies><dependency><groupId>org.neo4j</groupId><artifactId>neo4j-spatial</artifactId><version>2025.10.0</version></dependency></dependencies></profile>

The version specified on the version line can be changed to match the version you wish to work with (based on theversion of Neo4j itself you are using). To see which versions are available see the listatNeo4j Spatial Releases.

• start the GeoServer webapp again with the added neo4j profile

cd$GEOSERVER_SRC/src/web/app    mvn jetty:run -Pneo4j

• find Neo4j installed as a datasource underhttp://localhost:8080

For more info head over toNeo4j Wiki on uDig (This wiki iscurrently dead, but there appears to be a working mirror in Japanathttp://oss.infoscience.co.jp/neo4j/wiki.neo4j.org/content/Neo4j_Spatial_in_uDig.html).

The server plugin provides access to the internal spatial capabilities using three APIs:

• Procedures for much more comprehensive access to spatial from Cypher
  • Documentation is not yet available, but you can list the available procedures within Neo4j using thequeryCALL spatial.procedures
  • This API uses theProcedures capabilities released in Neo4j 3.0, and is therefor not available for Neo4j 2.x

During the Neo4j 3.x releases, support for spatial procedures changed a little,through the addition of various new capabilities.They were very quickly much more capable than the older REST API,making them by far the best option for accessing Neo4j remotely or through Cypher.

The Java API (the original API for Neo4j Spatial) still remains, however, the most feature rich,and therefor we recommend that if you need to access Neo4j server remotely, and want deeper access to Spatial functions,consider writing your own Procedures. The Neo4j 3.0 documentation provides some good information on how to do this,and you can also refer totheNeo4j Spatial procedures source codefor examples.

git clone https://github.com/neo4j-contrib/spatial/spatial.gitcd spatialmvn clean package

Some of the classes in Neo4j-Spatial include main() methods and can be run on the command-line.For example there are command-line options for importing SHP and OSM data. See the main methodsin the OSMImporter and ShapefileImporter classes. Here we will describe how to set up the dependenciesfor running the command-line, using the OSMImporter and the sample OSM file two-street.osm.We will show two ways to run this on the command line, one with the java command itself, and theother using the 'exec:java' target in maven. In both cases we use maven to set up the dependencies.

git clone git://github.com/neo4j-contrib/spatial.gitcd spatialmvn clean compile

mvn dependency:copy-dependenciesjava -cp target/classes:target/dependency/* org.neo4j.gis.spatial.osm.OSMImporter osm-db two-street.osm

Note: On windows remember to separate the classpath with ';' instead of ':'.

The first command above only needs to be run once, to get a copy of all required JAR files into the directorytarget/dependency.Once this is done, all further java commands with the -cp specifying that directory will load all dependencies.It is likely that the specific command being run does not require all dependencies copied, since it will only be usingparts of the Neo4j-Spatial library, but working out exactly which dependencies are required can take a little time, sothe above approach is most certainly the easiest way to do this.

mvn exec:java -Dexec.mainClass=org.neo4j.gis.spatial.osm.OSMImporter -Dexec.args="osm-db two-street.osm"

Note that the OSMImporter cannot re-import the same data multiple times,so you need to delete the database between runs if you are planning to do that.