Database Reference
In-Depth Information
Trythisqueryusing
ST_DWithin
insteadof
ST_3DDWithin
.You'llfindaninterest-
ingdifferenceinthenumberofpointsreturned,since
ST_DWithin
willcollectLiDAR
points that may be close to our streamline in the XY plane, but not as close when
looking at a 3D distance.
You can imagine
ST_3DWithin
querying within a tunnel around our line.
ST_DWithin
,bycontrast,isgoingtoqueryaverticalwallofLiDARpoints,asitis
only searching for adjacent points based on XY distance, ignoring height altogeth-
er, and, thus, gathering up all the points within a narrow wall above and below our
stream centerline.
