[postgis-users] How can I detect that geom != st_reverse(geom) for linestrings?
woodbri at swoodbridge.com
Wed Sep 2 13:23:30 PDT 2015
I just noticed that it is not obvious how to determine that
geom and st_reverse(geom) are different!
It seems that by definition st_equals(geom, st_reverse(geom)) is true as
is geom = st_reverse(geom). So this seems to be by definition, but it
brings up the question how to quickly and efficiently determine that
they are also different, even if they are "equal".
I'm doing st_astext(geom) != st_astext(st_reverse(geom)) but I worry
about precision issues doing this. I suppose I could also check if the
st_startpoint() of the two are the same, but that seems problematic also.
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