PostGIS 1.5.8 Manual - Fedora Project Packages GIT repositories

PostGIS 1.5.8 Manual33 / 310Interior Boundary ExteriorInteriordim(...) = 2 dim(...) = 1 dim(...) = 2Boundarydim(...) = 1 dim(...) = 0 dim(...) = 1Exteriordim(...) = 2 dim(...) = 1 dim(...) = 2Read from left to right and from top to bottom, the dimensional matrix is represented, ’212101212’.A relate matrix that would therefore represent our first example of two lines that intersect on a line would be: ’1*1***1**’-- Identify road segments that cross on a lineSELECT a.idFROM roads a, roads bWHERE a.id != b.idAND a.geom && b.geomAND ST_Relate(a.geom, b.geom, ’1*1***1**’);A relate matrix that represents the second example of wharfs partly on the lake’s shoreline would be ’102101FF2’-- Identify wharfs partly on a lake’s shorelineSELECT a.lake_id, b.wharf_idFROM lakes a, wharfs bWHERE a.geom && b.geomAND ST_Relate(a.geom, b.geom, ’102101FF2’);