Open cuteDen-ECNU opened 1 year ago
How about using this equation $MM^{T} = I$ and telling them $M$ is an orthogonal matrix? I think it may be more clear.
A visualized figure for Line a1
and Line a2
will also be good I think.
bugtracker link: https://trac.osgeo.org/postgis/ticket/5557
Potential bug in the ST_3DIntersects function.
29/9/2023
Geometry Description
Line a
('LINESTRING(5 4 0, 5 0 0)') intersectsLine b
('LINESTRING(6 4 0, 4 2 0)') atPoint c
(’POINT(5 3 0)’).We affine
Line a
andLine b
using the same orthogonal matrix $M$ and getLine a1
andLine b1
respectively.$M =\begin{pmatrix} -0.9248934130614574 & 0.2534855979991293 & 0.2834029394388001 \ -0.2259466894528656 & -0.9658860720787614 & 0.12653927963108094 \ 0.3058108369577812 & 0.05300139027692074 & 0.9506158975253333 \end{pmatrix}$
$M*M^T = E$
Expected Behavior
Line a1
andLine b1
should intersect atPoint c1
(affinePoint c
using $M$) because we only transform the coordinates.Point c1
is actually the intersection point ofLine a1
andLine b1
.Actual Behavior
PostGIS thinks that
Line a
andLine b
intersect, and doesn’t think thatLine a1
andLine b1
intersect.