st_3ddistance()

Category: Geospatial Functions Signature: st_3ddistance(geometry_a GEOMETRY, geometry_b GEOMETRY) → FLOAT Description: Returns the 3-dimensional minimum Cartesian distance between two geometries. If either geometry has no Z component, this is equivalent to ST_Distance with Z coordinates treated as 0.

Example: ```sql -- Distance between two 3D points SELECT ST_3DDistance('POINT Z(0 0 0)'::GEOMETRY, 'POINT Z(1 1 1)'::GEOMETRY); -- Returns: 1.7320508075688772

-- Z-only difference SELECT ST_3DDistance('POINT Z(0 0 0)'::GEOMETRY, 'POINT Z(0 0 5)'::GEOMETRY); -- Returns: 5

-- 2D geometries (Z treated as 0) SELECT ST_3DDistance('POINT(0 0)'::GEOMETRY, 'POINT(3 4)'::GEOMETRY); -- Returns: 5 ```

st_3ddwithin()

Category: Geospatial Functions Signature: st_3ddwithin(geometry_a GEOMETRY, geometry_b GEOMETRY, distance FLOAT) → BOOL Description: Returns true if any part of geometry_a is within distance units of geometry_b, using 3D Euclidean distance. This is equivalent to ST_3DDistance(geometry_a, geometry_b) <= distance.

Example: ```sql -- Check if 3D points are within distance SELECT ST_3DDWithin('POINT Z(0 0 0)'::GEOMETRY, 'POINT Z(1 1 1)'::GEOMETRY, 2.0); -- Returns: true

-- Check with exact distance threshold SELECT ST_3DDWithin('POINT Z(0 0 0)'::GEOMETRY, 'POINT Z(0 0 5)'::GEOMETRY, 5.0); -- Returns: true

-- Below threshold SELECT ST_3DDWithin('POINT Z(0 0 0)'::GEOMETRY, 'POINT Z(0 0 5)'::GEOMETRY, 4.0); -- Returns: false ```

_st_3ddwithin()

Category: Geospatial Functions Signature: _st_3ddwithin(geometry_a GEOMETRY, geometry_b GEOMETRY, distance FLOAT) → BOOL Description: Returns true if any part of geometry_a is within distance units of geometry_b, using 3D Euclidean distance. This variant does not utilize any spatial index and is intended for internal use or when spatial indexes should be bypassed.

Example: sql -- Internal variant without spatial index optimization SELECT _ST_3DDWithin('POINT Z(0 0 0)'::GEOMETRY, 'POINT Z(1 1 1)'::GEOMETRY, 2.0); -- Returns: true