Re: Exact circ×circ Hit on ExactCircularArc — keep CircularString as view?

[Daniel Baston]

Hi Jeroen,

I'm not really following what your proposal involves or how it differs from
the existing arc/arc intersection code. But if you want to flesh it out in
a GitHub issue or pull request, I can take a look at it.

Dan

On Tue, Sep 15, 2026 at 7:43 PM Jeroen Bloemscheer <
jeroen.bloemscheer at merkator.com> wrote:

> Hi,
>
> With curve types and CircularArcIntersector now in main, I’d like to
> propose a small, incremental addition—not an OverlayNG rewrite.
>
> Proposal: introduce a closed‑form circular arc/arc intersection
> implemented on an algorithm‑side ExactCircularArc value type in
> geos::algorithm::exactcurve (not a new geos::geom type). When two circular
> 3‑control windows properly cross, intersection vertices are added on each
> arc at the intersection points. geom::CircularString remains the WKT/WKB
> representation; the operation does not take geom::CircularString as input.
>
> No changes to the C API, ExactCurve, ArcNoder, or SegmentString.
>
> Out of scope: circular‑arc/chord interior intersections, buffering,
> overlay operations, and CIRCLE as a separate SQL/MM type.
>
> Refs: Discussion #1516; historical #1046 and #1382.
>
> Would opening a GitHub issue for this specific slice be useful, or would
> you prefer that I keep the work on a fork until there’s a concrete PR? I’ll
> only open an issue if you consider it helpful.
>
> Jeroen Bloemscheer
> Merkator / OSGeo bloemscheer
>
>
>
>
> ------------------------------
> *Jeroen Bloemscheer*
> Geo-IT Consultant
> Zaltbommel
>
> *[image: Merkator] *
>
> m: +31 (0)6 478 728 18
> e:  jeroen.bloemscheer at merkator.com
>
>
> Merkator BV
> Hogeweg 137a
> 5301 LL Zaltbommel(NL)
> www.merkator.com [image: LinkedIn]
> <https://www.linkedin.com/company/2400587>
> ------------------------------
>
> This email (including any attachments to it) is confidential, legally
> privileged, subject to copyright and is sent for the personal attention of
> the intended recipient only. If you have received this email in error,
> please advise us immediately and delete it. You are notified that
> disclosing, copying, distributing or taking any action in reliance on the
> contents of this information is strictly prohibited. Although we have taken
> reasonable precautions to ensure no viruses are present in this email, we
> cannot accept responsibility for any loss or damage arising from the
> viruses in this email or attachments. We exclude any liability for the
> content of this email, or for the consequences of any actions taken on the
> basis of the information provided in this email or its attachments, unless
> that information is subsequently confirmed in writing.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/geos-devel/attachments/20260915/e8e25e1f/attachment.htm>