Bug #36224 Within-Function gives wrong results - Point is wrongly in Polygon
Submitted: 20 Apr 2008 21:59 Modified: 22 Apr 2008 23:32
Reporter: Monty Muth
Status: Not a Bug
Category:Server: GIS Severity:S3 (Non-critical)
Version:5.1.24-rc OS:Microsoft Windows (XP SP2)
Assigned to: Target Version:
Tags: gis

[20 Apr 2008 21:59] Monty Muth 
Description:
The "Within" GIS-Function give me wrong results. It says that a point is within a
polygon, but in realy its not. 

How to repeat:
See the attachment, for variables and a example picture.

...> insert attachment variables <...

select within(@poin,@poly_outer);
The Result is 1;

But it should be 0, the Point is not in the Polygon;

The Coordinate Reference System is EPSG:31469 (DHDN / Gauss-Kruger zone 5)

PostgreSQL/Postgis gives me the right result (0) with the same data (st_within  
Function).
[20 Apr 2008 22:00] Monty Muth 
Within-function says the point is inside the polygon

Attachment: within_bug.PNG (image/png, text), 15.90 KiB.
[20 Apr 2008 22:02] Monty Muth 
Variables for Example

Attachment: within_bugtxt.txt (text/plain), 8.90 KiB.
[22 Apr 2008 22:44] Monty Muth 
I found a hint at http://forge.mysql.com/wiki/GIS_Functions:
"Most notably is that all functions that query spatial data only operate on MBRs (minimum
bounding rectangles), to simplify the operations.

Thanks to MySQL Developer Alexey "Holyfoot" Botchkov from Izhevsk, Russia, some of the
spatial relation functions like INTERSECTS and WITHIN now work in the way they are
described by OpenGIS and not by using MBR's as it used to be."

Has the 5.1.24-rc the new WITHIN Function from Holyfoot?
[22 Apr 2008 23:32] Monty Muth 
It's not a bug, "fixed" in GIS Version 5.1.23-gis.