ST_IsValidReason — Returns text stating if a geometry is valid or not and if not valid, a reason why.
text ST_IsValidReason(
geometry geomA)
;
text ST_IsValidReason(
geometry geomA, integer flags)
;
Returns text stating if a geometry is valid or not an if not valid, a reason why.
Useful in combination with ST_IsValid to generate a detailed report of invalid geometries and reasons.
Allowed flags
are documented in ST_IsValidDetail.
Availability: 1.4 - requires GEOS >= 3.1.0.
Availability: 2.0 - requires GEOS >= 3.3.0 for the version taking flags.
--First 3 Rejects from a successful quintuplet experiment SELECT gid, ST_IsValidReason(the_geom) as validity_info FROM (SELECT ST_MakePolygon(ST_ExteriorRing(e.buff), ST_Accum(f.line)) As the_geom, gid FROM (SELECT ST_Buffer(ST_MakePoint(x1*10,y1), z1) As buff, x1*10 + y1*100 + z1*1000 As gid FROM generate_series(-4,6) x1 CROSS JOIN generate_series(2,5) y1 CROSS JOIN generate_series(1,8) z1 WHERE x1 > y1*0.5 AND z1 < x1*y1) As e INNER JOIN (SELECT ST_Translate(ST_ExteriorRing(ST_Buffer(ST_MakePoint(x1*10,y1), z1)),y1*1, z1*2) As line FROM generate_series(-3,6) x1 CROSS JOIN generate_series(2,5) y1 CROSS JOIN generate_series(1,10) z1 WHERE x1 > y1*0.75 AND z1 < x1*y1) As f ON (ST_Area(e.buff) > 78 AND ST_Contains(e.buff, f.line)) GROUP BY gid, e.buff) As quintuplet_experiment WHERE ST_IsValid(the_geom) = false ORDER BY gid LIMIT 3; gid | validity_info ------+-------------------------- 5330 | Self-intersection [32 5] 5340 | Self-intersection [42 5] 5350 | Self-intersection [52 5] --simple example SELECT ST_IsValidReason('LINESTRING(220227 150406,2220227 150407,222020 150410)'); st_isvalidreason ------------------ Valid Geometry