| Bug #81964 | MySQL uses invalid WKT for empty geometrycollection | ||
|---|---|---|---|
| Submitted: | 22 Jun 2016 5:10 | Modified: | 12 Aug 2016 16:47 |
| Reporter: | Sergey Fedoseev | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: GIS | Severity: | S3 (Non-critical) |
| Version: | 5.7.5, 5.7.13 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[22 Jun 2016 11:54]
MySQL Verification Team
Hello Sergey Fedoseev, Thank you for the report! Thanks, Umesh
[12 Aug 2016 16:47]
Paul DuBois
Posted by developer: Noted in 8.0.0 changelog. Spatial functions for import and export of Well-Known Text (WKT) values used nonstandard 'GEOMETRYCOLLECTION()' syntax rather than OpenGIS standard 'GEOMETRYCOLLECTION EMPTY' syntax. Now both syntaxes are understood for import and the standard syntax is used for export.
Description: MySQL uses 'GEOMETRYCOLLECTION()' as WKT representation of empty geometry collection, though as stated in OpenGIS® Implementation Standard for Geographic information - Simple feature access - Part 1: Common architecture WKT for geometry collections are defined by the following BNF: <geometrycollection text> ::= <empty set> | <left paren> <geometry tagged text> {<comma> <geometry tagged text>}* <right paren> How to repeat: mysql> SELECT ST_AsText(ST_Intersection(ST_GeomFromText('POINT (0 0)'), ST_GeomFromText('POINT (1 1)'))); +--------------------------------------------------------------------------------------------+ | ST_AsText(ST_Intersection(ST_GeomFromText('POINT (0 0)'), ST_GeomFromText('POINT (1 1)'))) | +--------------------------------------------------------------------------------------------+ | GEOMETRYCOLLECTION() | +--------------------------------------------------------------------------------------------+ 1 row in set (0,00 sec) Suggested fix: MySQL should use 'GEOMETRYCOLLECTION EMPTY' as WKT representation of empty geometry collections.