[postgis-devel] POINT EMPTY in WKB

Paul Ramsey pramsey at opengeo.org
Mon Dec 6 12:30:31 PST 2010


On Mon, Dec 6, 2010 at 10:01 AM, Paul Ramsey <pramsey at opengeo.org> wrote:

> A final possibility would be to hack POINT EMPTY into WKB, as
> something like POINT(nan nan nan) or POINT(inf inf inf) or POINT(-0 -0
> -0). There would be a danger there in platforms that have different
> interpretations of what nan, inf or -0 are in binary.

I neglected to add a third possibility which would be to add another
flag to the EWKB type number to indicate the presence of an empty
geometry. This would also be backwards breaking since old-school EWKB
handlers would, even if they stripped off the high bits, receive what
to them was a degenerate piece of WKB (endian-int32 instead of
endian-int32-double-double)

P



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