From mtnclimb at gmail.com  Sat Apr  6 09:43:52 2024
From: mtnclimb at gmail.com (Martin Davis)
Date: Sat, 6 Apr 2024 09:43:52 -0700
Subject: Relate computer inconsistencies ?
In-Reply-To: <ZgHno8BIi-_tfDhx@c23>
References: <ZgHno8BIi-_tfDhx@c23>
Message-ID: <CAK2ens3tbCxbTbY47XaWxdZ618izi=oiVw2QKkqZQm6FPfm-4Q@mail.gmail.com>

Discussion here:
https://github.com/libgeos/geos/issues/968#issuecomment-2041134101

This could also be raised as a separate issue.

On Mon, Mar 25, 2024 at 2:07?PM Sandro Santilli <strk at kbt.io> wrote:

> I'm struggling with a robustness bug in PostGIS topology [1] which
> is making me question the relate computer of GEOS. Look at this:
>
>
> E=010200000002000000B02EA9C2AE5430400E3994256830514037F136E82055304039FAE86851305140
>
> I=01020000000200000064AB380D714E3040A38E9F0E1F305140E798A2D4E85430405F5969945C305140
>
>   geosop -a $E -b $I relate
>   # F01FF0102
>
>   # Interior of $E intersects the boundary if $I
>   #    I B E
>   #  I F 0 1
>   #  B F F 0
>   #  E 1 0 2
>
>   geosop -a $E -b $(geosop -f wkb -a $I boundary) relate
>   # FF1FF00F2
>
>   # Boundary of $I has no intersection with interior of $E
>   #    I B E
>   #  I F F 1
>   #  B F F 0
>   #  E 0 F 2
>
>
> So, where is that "boundary" intersection with 'i' ?
>
> [1] https://trac.osgeo.org/postgis/ticket/5699
>
> --strk;
>
>   Libre GIS consultant/developer
>   https://strk.kbt.io/services.html
>
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