Name

ST_IsValidDetail — Returns a valid_detail (valid,reason,location) row stating if a geometry is valid or not and if not valid, a reason why and a location where.

Synopsis

valid_detail ST_IsValidDetail(geometry geom);

valid_detail ST_IsValidDetail(geometry geom, integer flags);

Description

Returns a valid_detail row, formed by a boolean (valid) stating if a geometry is valid, a varchar (reason) stating a reason why it is invalid and a geometry (location) pointing out where it is invalid.

Useful to substitute and improve the combination of ST_IsValid and ST_IsValidReason to generate a detailed report of invalid geometries.

The 'flags' argument is a bitfield. It can have the following values:

• 1: Consider self-intersecting rings forming holes as valid. This is also know as "the ESRI flag". Note that this is against the OGC model.

Availability: 2.0.0 - requires GEOS >= 3.3.0.

Examples

--First 3 Rejects from a successful quintuplet experiment
SELECT gid, reason(ST_IsValidDetail(the_geom)), ST_AsText(location(ST_IsValidDetail(the_geom))) as location
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  |      reason       |  location
------+-------------------+-------------
5330 | Self-intersection | POINT(32 5)
5340 | Self-intersection | POINT(42 5)
5350 | Self-intersection | POINT(52 5)

--simple example
SELECT * FROM ST_IsValidDetail('LINESTRING(220227 150406,2220227 150407,222020 150410)');

valid | reason | location
-------+--------+----------
t     |        |