ST_IsValidReason — 返回说明几何图形是否有效或无效原因的文本。
text ST_IsValidReason(
geometry geomA)
;
text ST_IsValidReason(
geometry geomA, integer flags)
;
返回文本,说明几何图形是否有效,如果无效,则说明原因。
与 ST_IsValid 结合使用可生成无效几何形状和原因的详细报告。
允许的flags
记录在ST_IsValidDetail 中。
这个函数是由 GEOS 模块执行的。
可用性:1.4
有效性:2.0 版本正在接受标记。
-- invalid bow-tie polygon SELECT ST_IsValidReason( 'POLYGON ((100 200, 100 100, 200 200, 200 100, 100 200))'::geometry) as validity_info; validity_info -------------------------- Self-intersection[150 150]
--First 3 Rejects from a successful quintuplet experiment SELECT gid, ST_IsValidReason(geom) as validity_info FROM (SELECT ST_MakePolygon(ST_ExteriorRing(e.buff), array_agg(f.line)) As geom, gid FROM (SELECT ST_Buffer(ST_Point(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_Point(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(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