ST_ndDWithin函數(shù)，判斷指定的兩個對象在指定的坐標軸上是否距離小于等于某一給定值。

語法

bool ST_{2D|3D}DWithin(geometry geom, trajectory traj, float8 dist);
bool ST_{2D|3D}DWithin(trajectory traj, geometry geom, float8 dist);
bool ST_{2D|3D}DWithin(geometry geom, trajectory traj, timestamp ts, timestamp te, float8 dist);
bool ST_{2D|3D}DWithin(trajectory traj, geometry geom, timestamp ts, timestamp te, float8 dist);
bool ST_{2D|2DT|3D|3DT}DWithin(boxndf box, trajectory traj, float8 dist);
bool ST_{2D|2DT|3D|3DT}DWithin(trajectory traj, boxndf box, float8 dist);
bool ST_{2D|2DT|3D|3DT}DWithin(boxndf box, trajectory traj, timestamp ts, timestamp te, float8 dist);
bool ST_{2D|2DT|3D|3DT}DWithin(trajectory traj, boxndf box, timestamp ts, timestamp te, float8 dist);
bool ST_{2D|2DT|3D|3DT}DWithin(trajectory traj1, trajectory traj2, float8 dist);
bool ST_{2D|2DT|3D|3DT}DWithin(trajectory traj1, trajectory traj2, timestamp ts, timestamp te, float8 dist);

參數(shù)

參數(shù)名稱 描述
geom 需要判斷的幾何對象。
traj 需要判斷的軌跡對象，或者產(chǎn)生子軌跡的原始軌跡。
traj1 需要判斷的軌跡對象，或者產(chǎn)生子軌跡的原始軌跡。
traj2 需要判斷的軌跡對象，或者產(chǎn)生子軌跡的原始軌跡。
box 需要判斷的外包框對象。
ts 如存在，表示按此時間作為開始時間截取子軌跡。
te 如存在，表示按此時間作為結束時間截取子軌跡。
dist 距離的臨界值。

描述

  • 對于2D和3D的ST_ndDWithin操作，我們判斷給定的兩個對象（即第一個和第二個參數(shù)）在二維/三維空間上的投影（即對應的geometry類型）是否距離小于等于給定值。
  • 對于2DT和3DT的ST_ndDWithin操作，我們判斷兩者是否在某一時間點上在指定維度上的距離小于等于過給定值。

如果函數(shù)包含ts和te參數(shù)，代表判斷ST_ndDWithin的軌跡對象（traj，或traj1和traj2）是在[ts,te]時間段內的子軌跡；否則則表示需要判斷的軌跡對象（traj，或traj1和traj2）是完整的軌跡。

直接調用ST_DistanceWithin(..)函數(shù)相當于調用ST_2DDWithin(...)（若前兩個參數(shù)其中一個為幾何對象）或ST_3DTDWithin(...)（若前兩個參數(shù)均為軌跡對象）。

示例

WITH traj AS(
    Select ST_makeTrajectory('STPOINT', 'LINESTRING(0 0 10, 50 0 10, 100 0 10)'::geometry,
                             ('[' || ST_PGEpochToTS(0) || ',' || ST_PGEpochToTS(100) || ')')::tsrange,
                             '{"leafcount":3,"attributes":{"velocity": {"type": "integer", "length": 2,"nullable" : true,"value": [120,130,140]}, "accuracy": {"type": "float", "length": 4, "nullable" : false,"value": [120,130,140]}, "bearing": {"type": "float", "length": 8, "nullable" : false,"value": [120,130,140]}, "acceleration": {"type": "string", "length": 20, "nullable" : true,"value": ["120","130","140"]}, "active": {"type": "timestamp", "nullable" : false,"value": ["Fri Jan 01 11:35:00 2010", "Fri Jan 01 12:35:00 2010", "Fri Jan 01 13:30:00 2010"]}}, "events": [{"2" : "Fri Jan 02 15:00:00 2010"}, {"3" : "Fri Jan 02 15:30:00 2010"}]}') a,
           ST_makeTrajectory('STPOINT', 'LINESTRING(0 20, 50 20, 100 20)'::geometry,
                             ('[' || ST_PGEpochToTS(0) || ',' || ST_PGEpochToTS(100) ||')')::tsrange,
                             '{"leafcount":3,"attributes":{"velocity": {"type": "integer", "length": 2,"nullable" : true,"value": [120,130,140]}, "accuracy": {"type": "float", "length": 4, "nullable" : false,"value": [120,130,140]}, "bearing": {"type": "float", "length": 8, "nullable" : false,"value": [120,130,140]}, "acceleration": {"type": "string", "length": 20, "nullable" : true,"value": ["120","130","140"]}, "active": {"type": "timestamp", "nullable" : false,"value": ["Fri Jan 01 11:35:00 2010", "Fri Jan 01 12:35:00 2010", "Fri Jan 01 13:30:00 2010"]}}, "events": [{"2" : "Fri Jan 02 15:00:00 2010"}, {"3" : "Fri Jan 02 15:30:00 2010"}]}') b
)
SELECT ST_2dDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(49), 19), ST_3dDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(49), 19),
       ST_2dDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(50), 20), ST_3dDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(50), 20),
       ST_2dDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(70), 21), ST_3dDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(70), 21),
       ST_2dtDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(49), 19), ST_3dtDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(49), 19),
       ST_2dtDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(50), 20), ST_3dtDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(50), 20),
       ST_2dtDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(70), 21), ST_3dtDWithin(a,b, ST_PGEpochToTS(0),ST_PGEpochToTS(70), 21) from traj;
NOTICE:  One or both of the geometries is missing z-value. The unknown z-value will be regarded as "any value"
NOTICE:  One or both of the geometries is missing z-value. The unknown z-value will be regarded as "any value"
 st_2ddwithin | st_3ddwithin | st_2ddwithin | st_3ddwithin | st_2ddwithin | st_3ddwithin | st_2dtdwithin | st_3dtdwithin | st_2dtdwithin | st_3dtdwithin | st_2dtdwithin | st_3dtdwithin 
--------------+--------------+--------------+--------------+--------------+--------------+---------------+---------------+---------------+---------------+---------------+---------------
 f            | f            | t            | t            | t            | t            | f             | f             | t             | t             | t             | t