Building Spatial Search Algorithms for Neo4j Craig Taverner Neo4j - - PowerPoint PPT Presentation
Building Spatial Search Algorithms for Neo4j Craig Taverner Neo4j Cypher and Spatial @craigtaverner Agenda Two Minute History Neo4j 3.4 WITH point({latitude: 55.612149, longitude: 12.995090}) AS poi MATCH
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WITH point({latitude: 55.612149, longitude: 12.995090}) AS poi MATCH (l:Location)<-[:AT]-(b:Business)-[:OF]->(c:Category) WHERE c.name = "coffee" AND distance(l.location, poi) < 10000 RETURN distance(l.location, poi) as distance, b.name as coffee_shop ORDER BY distance DESC
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WITH point({latitude: 55.612149, longitude: 12.995090}) AS poi MATCH (l:Location)<-[:AT]-(b:Business)-[:OF]->(c:Category) WHERE c.name = "coffee" AND distance(l.location, poi) < 10000 RETURN distance(l.location, poi) as distance, b.name as coffee_shop ORDER BY distance DESC
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LocalDateTime)
Neo4j 3.4 focuses on very specific use case:
WITH point({latitude: 55.612149, longitude: 12.995090}) AS poi MATCH (l:Location)<-[:AT]-(b:Business)-[:OF]->(c:Category) WHERE c.name = "coffee" AND distance(l.location, poi) < 10000 RETURN distance(l.location, poi) as distance, b.name as coffee_shop ORDER BY distance DESC 9 index 5 hits
https://neo4j.com/docs/cypher-manual/current/functions/spatial/
https://neo4j.com/docs/cypher-manual/current/syntax/spatial/
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MATCH (a:PointOfInterest) WHERE a.name = 'The View Restaurant & Lounge' MATCH (b:PointOfInterest) WHERE b.name = 'Gregory Coffee' MATCH p=shortestPath((a)-[:ROUTE*..100]-(b)) RETURN p;
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https://neo4j.com/docs/developer-manual/3.4/cypher/execution-plans/shortestpath-planning/
MATCH (a:PointOfInterest) WHERE a.name = 'The View Restaurant & Lounge' MATCH (b:PointOfInterest) WHERE b.name = 'Gregory Coffee' MATCH p=shortestPath((a)-[:ROUTE*..100]-(b)) RETURN p;
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Total weight: 1258.48m
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MATCH (m:OSMRelation) WHERE m.name = 'Manhattan' MATCH (p:PointOfInterest) WHERE distance(p.location,$mapCenter) < $circleRadius AND amanzi.withinPolygon(m.polygon,p.location) RETURN p
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MATCH (m:OSMRelation) WHERE m.name = 'Manhattan' WITH m.polygon as manhattan, amanzi.boundingBoxFor(m.polygon) as bbox MATCH (p:PointOfInterest) WHERE bbox.min < p.location < bbox.max AND amanzi.withinPolygon(manhattan,p.location) RETURN p
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X X X X X
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https://vanderbei.princeton.edu/WebGL/GirardThmProof.html
MATCH (r:OSMRelation)-[:POLYGON_STRUCTURE*]->(p) USING INDEX r:OSMRelation(relation_osm_id) WHERE r.relation_osm_id IN $regionIds AND exists(p.polygon) RETURN r.relation_osm_id AS region_id, spatial.algo.area(p.polygon) AS area;
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UNWIND $pairs AS pair MATCH (r1:OSMRelation)-[:POLYGON_STRUCTURE*]->(p1) USING INDEX r1:OSMRelation(relation_osm_id) WHERE r1.relation_osm_id=pair[0] AND exists(p1.polygon) OPTIONAL MATCH (r2:OSMRelation)-[:POLYGON_STRUCTURE*]->(p2) USING INDEX r2:OSMRelation(relation_osm_id) WHERE r2.relation_osm_id=pair[1] AND exists(p2.polygon) RETURN pair, spatial.algo.distance.ends(p1.polygon, p2.polygon) AS distance;
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MATCH (r:OSMRelation)-[:POLYGON_STRUCTURE*]->(p) USING INDEX r:OSMRelation(relation_osm_id) WHERE r.relation_osm_id IN $regionIds AND exists(p.polygon) RETURN p.polygon as region;
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MATCH (r:OSMRelation)-[:POLYGON_STRUCTURE*]->(p) USING INDEX r:OSMRelation(relation_osm_id) WHERE r.relation_osm_id IN $regionIds AND exists(p.polygon) RETURN spatial.algo.convexHull(p.polygon) as region;
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1. Easy: What is the difference between Cartesian and Geographic Coords?
a. Cartesian uses latitude and longitude while geographic uses x and y b. Cartesian is euclidean while geographic uses polar coordinates c. They are actually the same
2. Medium: Which library has the most spatial algorithms?
a. Old “Neo4j Spatial” from 2010 b. OpenStreetMap importing library c. New “Spatial Algorithms” library from 2019
3. Hard: What is the name of the function to calculate the distance between polygons and return the result together with the two closest points? Answer here: r.neo4j.com/hunger-games
Links to the demo application as well as library used in the data modeling and building of the app:
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https://github.com/neo4j-contrib/osm
java -Xms1280m -Xmx1280m \
IMPORT DONE in 2m 31s 430ms. Imported: 21401587 nodes 22647165 relationships 53754931 properties Peak memory usage: 1.24 G
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CREATE INDEX ON :OSMTags(amenity); ← collect relevant points of interest CREATE INDEX ON :OSMTags(description); CREATE INDEX ON :OSMTags(food); CREATE INDEX ON :OSMTags(highway); ← route graph limited to streets CREATE INDEX ON :OSMTags(restaurant); CREATE INDEX ON :Intersection(location); ← help find routes CREATE INDEX ON :Routable(location); ← help find routes CREATE INDEX ON :PointOfInterest(location); ← help find routes CREATE INDEX ON :OSMNode(location); CREATE INDEX ON :PointOfInterest(name); ← search for points of interest
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MATCH (awn:OSMWayNode)-[r:NEXT]-(bwn:OSMWayNode) WHERE NOT exists(r.distance) WITH awn,bwn,r LIMIT 10000 MATCH (awn)-[:NODE]->(a:OSMNode), (bwn)-[:NODE]->(b:OSMNode) SET r.distance=distance(a.location,b.location) RETURN COUNT(*);
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CALL apoc.periodic.iterate( 'MATCH (awn:OSMWayNode)-[r:NEXT]-(bwn:OSMWayNode) WHERE NOT exists(r.distance) RETURN awn,bwn,r', 'MATCH (awn)-[:NODE]->(a:OSMNode), (bwn)-[:NODE]->(b:OSMNode) SET r.distance=distance(a.location,b.location)', {batchSize:10000, parallel:false});
MATCH (awn:OSMWayNode)-[r:NEXT]-(bwn:OSMWayNode) WHERE NOT exists(r.distance) WITH awn,bwn,r LIMIT 10000 MATCH (awn)-[:NODE]->(a:OSMNode), (bwn)-[:NODE]->(b:OSMNode) SET r.distance=distance(a.location,b.location) RETURN COUNT(*);
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MATCH (n:OSMNode) WHERE size((n)<-[:NODE]-()) > 2 AND NOT (n:Intersection) WITH n LIMIT 100 MATCH (n)<-[:NODE]-(wn:OSMWayNode), (wn)<-[:NEXT*0..100]-(wx), (wx)<-[:FIRST_NODE]-(w:OSMWay)-[:TAGS]->(wt:OSMTags) WHERE exists(wt.highway) SET n:Intersection RETURN count(*);
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MATCH (x:Intersection) WITH x LIMIT 100 CALL spatial.osm.routeIntersection(x,true,false,false) YIELD fromNode, toNode, distance, fromRel, toRel WITH fromNode, toNode, distance, fromRel, toRel MERGE (fromNode)-[r:ROUTE {fromRel:id(fromRel),toRel:id(toRel)}]->(toNode) ON CREATE SET r.distance = distance RETURN count(*);
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UNWIND ["restaurant","fast_food","cafe","bar","pub","ice_cream","cinema"] AS amenity MATCH (x:OSMNode)-[:TAGS]->(t:OSMTags) WHERE t.amenity = amenity AND NOT (x)-[:ROUTE]->() WITH x, x.location as poi LIMIT 100 MATCH (n:OSMNode) WHERE distance(poi, n.location) < 100 WITH x, n MATCH (n)<-[:NODE]-(wn:OSMWayNode), (wn)<-[:NEXT*0..10]-(wx), (wx)<-[:FIRST_NODE]-(w:OSMWay)-[:TAGS]->(wt:OSMTags) WITH x, w, wt WHERE exists(wt.highway) WITH x, collect(w) as ways CALL spatial.osm.routePointOfInterest(x,ways) YIELD node SET x:PointOfInterest RETURN count(node);
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MATCH (x:Routable:OSMNode) WHERE NOT (x)-[:ROUTE]->(:Intersection) WITH x LIMIT 100 CALL spatial.osm.routeIntersection(x,true,false,false) YIELD fromNode, toNode, fromRel, toRel, distance, length, count WITH fromNode, toNode, fromRel, toRel, distance, length, count MERGE (fromNode)-[r:ROUTE {fromRel:id(fromRel),toRel:id(toRel)}]->(toNode) ON CREATE SET r.distance = distance, r.length = length, r.count = count RETURN count(*);
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MATCH (a:PointOfInterest) WHERE a.name = 'The View Restaurant & Lounge' MATCH (b:PointOfInterest) WHERE b.name = 'Gregory Coffee' MATCH p=shortestPath((a)-[:ROUTE*..100]-(b)) RETURN p;
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