ST_Distance() query error

[Paul Ramsey]

I can confirm reproducing this bug. The shapes are close, but the distance
is non-zero throughout.

Ticketed here.

https://trac.osgeo.org/postgis/ticket/5989

P
[image: Screenshot 2025-09-18 at 10.33.46 AM.png]

On Mon, Sep 15, 2025 at 8:18 AM Paul Ramsey <pramsey at cleverelephant.ca>
wrote:

> This seems. net new. I haven’t verified locally, but I assume you’ve found
> something.
> There is not any ongoing development on arc distances, but we do work on
> verified bugs as a matter of course. You can speed things up, as always, by
> shrinking your demonstration case. The fewer vertices I have to wade
> through, the faster the cause can be identified.
> ATB,
> P
>
> On Sep 15, 2025, at 3:43 AM, Juho Rekilä via postgis-users <
> postgis-users at lists.osgeo.org> wrote:
>
> Hi,
>
> The ST_Distance() query below gives the result of 0 m for the distance
> between two features. The result is wrong as the features are actually
> approximately 0,2 meters away from each other.
>
> This error is also problematic because Geoserver now uses the
> ST_Distance() function when searching for objects that are touching each
> other, for example.
>
> The PostgreSQL and PostGIS versions used:
> PostgreSQL 17.5 (Ubuntu 17.5-1.pgdg24.04+1) on x86_64-pc-linux-gnu,
> compiled by gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0, 64-bit
> POSTGIS="3.5.3 aab5f55" [EXTENSION] PGSQL="170" GEOS="3.12.1-CAPI-1.18.1"
>
> The ST_Distance() query:
>
> SELECT
>   ST_Distance(
>
> ST_GeomFromText('MULTISURFACE(CURVEPOLYGON(COMPOUNDCURVE(CIRCULARSTRING(25498687.296406467
> 6679794.584487298,25498670.728066746 6679772.920079741,25498652.7219
> 6679752.4351),(25498652.7219 6679752.4351,25498649.618
> 6679749.1379,25498615.3055 6679712.6856,25498584.874
> 6679680.3574),CIRCULARSTRING(25498584.874 6679680.3574,25498575.9211
> 6679678.4791,25498571.0593 6679686.228),(25498571.0593
> 6679686.228,25498572.5718 6679717.5059,25498572.5935
> 6679717.9476,25498572.6156 6679718.3893),CIRCULARSTRING(25498572.6156
> 6679718.3893,25498575.9546 6679753.1238,25498582.4167
> 6679787.4148,25498582.6547 6679788.418,25498582.8953
> 6679789.4206),(25498582.8953 6679789.4206,25498583.4717
> 6679791.8086,25498577.35416496 6679793.28540422),(25498577.35416496
> 6679793.28540422,25498558 6679652,25498706 6679794,25498687.296406467
> 6679794.584487298))))', 3879)
>     ,ST_GeomFromText('POLYGON((25498577.925067347
> 6679764.376426865,25498577.31346041 6679760.722689815,25498576.736966014
> 6679757.06324837,25498576.19563731 6679753.398439955,25498575.68952422
> 6679749.72860249,25498575.218673404 6679746.054074359,25498574.783128276
> 6679742.375194377,25498574.382929 6679738.692301761,25498574.01811248
> 6679735.005736099,25498573.68871235 6679731.315837314,25498573.394758984
> 6679727.622945643,25498615.249195762 6679712.917382107,25498649.317714863
> 6679749.110582217,25498629.859234665 6679763.425791496,25498626.597285368
> 6679765.4664939325,25498616.53215853 6679754.940559511,25498616.475998268
> 6679754.899373339,25498616.40912013 6679754.879941631,25498616.33963356
> 6679754.884620618,25498577.925067347 6679764.376426865))', 3879)
>     ) AS dist
>
> Have you encountered this issue before and is there an ongoing development
> that will address this?
>
> Kind regards,
> Juho
> *Gispo Finland Ltd.*
> *https://www.gispo.fi/ <https://www.gispo.fi/>*
>
>
>
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