[geos-devel] Is Overlay-NG active?

[Paul Ramsey]

The "plan" as I see it is to, for 3.9, actually make NG the default for the standard intersection(), union(), unaryunion(), difference(), symdifference() calls. So the "test" will be "is this GEOS 3.9". I don't want to go forward into the future where a released GEOS has two potential behaviour modes, that way lies madness. We needed to keep a switch in place to allow other development to continue and to compare before/after easily on the working branch (and to allow people like you to test the new without suddenly have everything break on ordinary testing).

Does that make sense?

P

> On Oct 15, 2020, at 8:59 AM, Roger Bivand <Roger.Bivand at nhh.no> wrote:
> 
> Can I ask whether there is, or could be, a function exposed in the C_API, or a header variable say in geoc_c.h, showing whether the running GEOS is using Overlay-NG or not?
> 
> After help from the list, I've now run checks on R packages either themselves linking to GEOS, or using functions from packages which do link to GEOS. A half-dozen or so fail on unit tests, typically because the ordering  of coordinates varies (say same polygon, but starting at  a different place), or the ordering of sub-geometries (say slivers from a Union operation) varies from before Overlay-NG. The objects are the same (for given precision), but unit tests in packages compare the WKT of the output geometry with the expected WKT (often generated from output before Overlay-NG).
> 
> So if we could provide a way for the unit tests to compare correctly branching on Overlay-NG or not, the package maintainers could avoid having to scramble when platforms and R packages linking to GEOS begin to appear.
> 
> Another question raised by package maintainers - do we know when 3.9.0 may be expected, and will it have Overlay-NG? However, providing them with an easy way to ask the GEOS runtime if it is Overlay-NG or not will relieve the pressure.
> 
> Anyway, the failure count is very low, a half-dozen from hundreds is fine (and if they didn't write tests, that isn't our problem...).
> 
> Roger
> 
> -- 
> Roger Bivand
> Department of Economics, Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; e-mail: Roger.Bivand at nhh.no
> https://orcid.org/0000-0003-2392-6140
> https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en
> _______________________________________________
> geos-devel mailing list
> geos-devel at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/geos-devel