On Wed, Sep 07, 2022 at 03:44:10PM -0700, Martin Davis wrote: > On Wed, Sep 7, 2022 at 3:18 PM Sandro Santilli <s...@kbt.io> wrote: > > > On Tue, Sep 06, 2022 at 02:37:37PM -0700, Martin Davis wrote: > > > I've started to build out operations on Polygonal Coverages in JTS ([1], > > > [2]). > > > > [...] > > > > > A key question is how to expose these operations in the GEOS C API. I > > see > > > two options: > > > 1) Model a Polygonal Coverage as an array of simple Polygons (and > > possibly > > > MultiPolygons) > > > 2) Provide a Polygonal Coverage datatype (which might contain internal > > > topology) > > > > Could a coverage datatype allow performing operations on PostGIS Topologies > > w/out building the polygons for each face ? > > > The short answer is "yes, probably, if suitable builders are defined for > the coverage datatype". But that starts getting complex (in particular, it > probably requires a concept of a Face, which might also have to be > exposed). This is quite a bit more design than the current work requires.
It really depends on what you mean by "Coverage" really. All I'm hoping for is that when using TopoGeometry objects I don't have to build Geometry objects from them for the SOLE PURPOSE of feeding them to GEOS which on its side would re-compute noding and labeling which was already known by the TopoGeometry objects itself. > > There's an ISO standard > > representation of topologies, maybe such representation could be used > > to transfer those topologies back and forth with GEOS ? > > Not familiar with that representation. How does it handle identity for > Faces of topologies? Faces are identified by an integer value, referenced by edges (attributes: left_face, right_face) See http://strk.kbt.io/projects/postgis/topology-ER.pdf --strk; _______________________________________________ geos-devel mailing list geos-devel@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/geos-devel
