On Wed, Jun 1, 2016 at 7:52 AM, Jim Nasby <jim.na...@bluetreble.com> wrote:
> > I suspect another wrinkle here is that in the GIS world a single point can > be represented it multiple reference/coordinate systems, and it would have > different values in each of them. AIUI the transforms between those systems > can be rather complicated if different projection methods are involved. I > don't know if PostGIS depends on what these macros are doing or not. If it > doesn't, perhaps it would be sufficient to lop of the last few bits of the > significand. ISTM that'd be much better than what the macros currently do. We don't depend on these, we have our own :/ The real answer for a GIS system is to have an explicit tolerance parameter for calculations like distance/touching/containment, but unfortunately we didn't do that so now we have our own compatibility/boil the ocean problem if we ever wanted/were funded to add one. P. > BTW, I suspect the macro values were chosen specifically for dealing with > LAT/LONG. > -- > Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX > Experts in Analytics, Data Architecture and PostgreSQL > Data in Trouble? Get it in Treble! http://BlueTreble.com > 855-TREBLE2 (855-873-2532) mobile: 512-569-9461 > > > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
