[geos-devel] CoverageUnion

[Daniel Baston]

I noticed that the OverlayNG coverage union returns an empty polygon if the
inputs do not form a coverage, whereas the older algorithm produces an
error. I think it would be a good idea to apply an area post-check to the
NG version so that we retain the error. I have also noticed cases (TIGER
county boundaries) where the NG algorithm takes about 2x as long as the old
algorithm but performs better than the old algorithm if the inputs are
pre-sorted (as they are in the old algorithm). Maybe the same sorting
should be added to the NG version.

Otherwise I have no reservations about switching.

Dan

On Tue, Apr 18, 2023 at 7:05 PM Martin Davis <mtnclimb at gmail.com> wrote:

> geos/coverage/CoverageUnion in fact delegates to
> geos/operation/overlayng/CoverageUnion.  It's there to provide an API which
> is the same as the other coverage operations.
>
> overlayng/CoverageUnion seems to be quite a bit faster than
> geos/operation/union/CoverageUnion, by my testing.  So it has my vote.(They
> are both exposed in geosop, so independent verification is welcome.)
>
> On Tue, Apr 18, 2023 at 3:56 PM Paul Ramsey <pramsey at cleverelephant.ca>
> wrote:
>
>> We have quite a few of them? Which one should be keep and bind into CAPI?
>>
>> geos/operation/union/CoverageUnion.h
>> geos/operation/overlayng/CoverageUnion.h
>> geos/coverage/CoverageUnion.h
>> _______________________________________________
>> geos-devel mailing list
>> geos-devel at lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/geos-devel
>>
> _______________________________________________
> geos-devel mailing list
> geos-devel at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/geos-devel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/geos-devel/attachments/20230418/56ded38c/attachment.htm>