[postgis-devel] Postgis "Split" with tolerance

[Sandro Santilli]

On Thu, Nov 28, 2013 at 05:22:11PM +0100, Rémi Cura wrote:
> Hey everybody,
> 
> again tolerance issue ! what !  ;-)
> 
> In the liblwgeom.c file ,
> I changed
> "if ( dist > 0)   /* TODO: accept a tolerance ? */"
> 
> to
> 
> //@TOTEST @CHECK change by Remi-C : adding a small tolerance
> vstol = ptarray_length_2d(lwline_in->points) / 1e12; //note : we don't
> really need to compute length, we could just compute
> //max (abs(max(x)-min(x)) , abs(max(y)-min(y)) ), it would be way faster
> if ( dist > vstol )   /* TODO: accept a tolerance ? */
> 
> 
> So know we can split a line by a point !
> Any thought?

Again, "accept" != "calculate".

I'm happy with exposing tolerance-computing functions, as I did
for topology with the _st_mintolerance or whatever I called it
(ok, that's not really "exposed"), but the point of that comment
is that ST_Split could take an optional tolerance from the user.

--strk;