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Jia Yu commented on SEDONA-178: ------------------------------- [~umartin] Yes, SQL distance join internally uses circle object, which was a silly design of mine long time ago. It only gives correct results when both sides are points. To get the correct result + optimized Sedona join performance, please use ST_Buffer as the workaround as [~Kontinuation] suggested. > Correctness issue in distance join queries > ------------------------------------------ > > Key: SEDONA-178 > URL: https://issues.apache.org/jira/browse/SEDONA-178 > Project: Apache Sedona > Issue Type: Bug > Reporter: Martin Andersson > Priority: Major > > Hi, > We are seeing erroneous results for some distance join queries. > > Case 1: > The following query gives no output even though the distance between the > geometries is 1. > {{select *}} > {{from (select ST_LineFromText('Linestring(1 1, 1 4)') as geom) a}} > {{join (select st_point(1.0,5.0) as geom) b}} > {{on st_distance(a.geom, b.geom) < 1.4}} > I think the issue boils down to a misuse of/error in Circle class. > DistanceJoinExec.scala:60 will create a Circle from the linestring and a > radius of 1.4. > Circle will compute the center point (1 2.5) and radius (1.5) for the > linestring. The actual radius used is max(radius(linestring), 1.4). See > Circle.java:80 > For the query to work the Circle needs a radius 1.4 _larger_ than the > linestring. Like this: > circle = new Circle(geom, 0.0); > circle.setRadius(circle.getRadius() + 1.4) > > Case 2: > The following query matches the geometries even though the distance is not > less than 0.1. Actual distance is 1. > {{select *}} > {{from (select ST_LineFromText('Linestring(1 1, 1 3, 3 3)') as geom) a}} > {{join (select st_point(2.0,2.0) as geom) b}} > {{on st_distance(a.geom, b.geom) < 0.1}} > Pseudo code for the join condition: > new Circle(a.geom, 0.1).covers(b.geom) > The circle does cover the point but the linestring is further away from the > point than 0.1 > -- This message was sent by Atlassian Jira (v8.20.10#820010)