[#MDEV-25132] centroid not even close to polygon in some cases

In some not so rare cases, when trying to get a centroid of a polygon, the point it returns is not even close to the polygon example:

SELECT AsText(ST_Centroid(ST_GeomFromText('POLYGON((141.473127 -31.949235,141.47322 -31.949187,141.473232 -31.949181,141.473238 -31.949186,141.473244 -31.94919,141.473254 -31.949198,141.473269 -31.94921,141.473311 -31.949243,141.47322 -31.949235,141.473231 -31.949199,141.473127 -31.949235))')))

Have tested this on MariaDB ver: 10.3.27 (what i'm using) and latest stable (10.5.9)

it shows a point ~600m away from the polygon. trying the exact same on MySQL ver: 5.7.20 & 8.0.22, the point is where you would expect it.

  "type": "FeatureCollection",

  "features": [

      "type": "Feature",

      "properties": {"name": "centroid", "version": "MariaDB 10.3.27"},

      "geometry": {

        "type": "Point",

        "coordinates": [141.4804016259371, -31.950833470712737]

},

      "type": "Feature",

      "properties": {"name": "centroid", "version": "MariaDB 10.5.9"},

      "geometry": {

        "type": "Point",

        "coordinates": [141.4804016259371, -31.950833470712737]

},

      "type": "Feature",

      "properties": {"name": "centroid", "version": "MySQL 5.7.20"},

      "geometry": {

        "type": "Point",

        "coordinates": [141.47323905138515, -31.949215928358655]

},

      "type": "Feature",

      "properties": {"name": "polygon"},

      "geometry": {

        "type": "Polygon",

        "coordinates": [[[141.473127, -31.949235], [141.47322, -31.949187], [141.473232, -31.949181], [141.473238, -31.949186], [141.473244, -31.94919], [141.473254, -31.949198], [141.473269, -31.94921], [141.473311, -31.949243], [141.47322, -31.949235], [141.473231, -31.949199], [141.473127, -31.949235]]]}

It seems to be random, alter the polygon a little and it will work. its not just a freak accident as it has been brought up to me 8-10 times is the few months we have been using MariaDB over MySQL

[MDEV-25132] centroid not even close to polygon in some cases Created: 2021-03-14 Updated: 2023-04-27
Status:	Confirmed
Project:	MariaDB Server
Component/s:	GIS
Affects Version/s:	10.3.27, 10.5.9, 10.2, 10.3, 10.4, 10.5
Fix Version/s:	10.4, 10.5

[MDEV-25132] centroid not even close to polygon in some cases Created: 2021-03-14 Updated: 2023-04-27