Re: boost::geometry: intersection of a point with a linestring

From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2019-10-04 09:00:42

On Fri, 4 Oct 2019 at 10:53, Giorgino R <giorginor21_at_[hidden]> wrote:

> Your example is exactly what I was thinking as a solution.
>
However, I just wanted to know whether an "optimised split" algorithm has
> been implemented. The PostGIS link was very helpful as well.
>

I'm not aware of any, but this you can check (or hope) if the `intersect`
function is
optimised for point and line case, calculating distance.
I can't remember or am not up to date myself on that.

You may want to post question specifically about to Boost.Geometry mailing
list
https://lists.boost.org/mailman/listinfo.cgi/geometry
(actually, much better place to discuss BG issues, than general
boost-users).

If not, you can try to optimise the proposed solution by testing easy to
optimise
and shortcut cases yourself. It may be a good idea to learn from PostGIS
again,
see what the ST_Split function does. For line and point case,
ST_Split is implemented in terms of this function

https://github.com/postgis/postgis/blob/86057e2e46a272838a54eff9e6ebb5e56f33fab7/liblwgeom/lwgeom_geos_split.c#L220-L231

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net