對(duì)一條軌跡重采樣。

語法

trajectory ST_Resample(trajectory traj, config);

參數(shù)

參數(shù)名稱 描述
traj 被切分的軌跡對(duì)象。
config 切分軌跡的規(guī)則。格式{"規(guī)則":"取值"}。
目前包含以下可選規(guī)則，每次調(diào)用此函數(shù)時(shí)，僅可選擇一個(gè)規(guī)則：
規(guī)則名稱 參數(shù)類型 說明
add_point.distance_lesser 浮點(diǎn)數(shù) 在每條軌跡線上均勻添加點(diǎn)，使每一段之間的距離均小于參數(shù)。
add_point.period_lesser 可以轉(zhuǎn)化為Interval類型的字符串 在每條軌跡線上均勻添加點(diǎn)，使每一段的時(shí)長(zhǎng)均小于參數(shù)。
drop_point.distance_lesser 浮點(diǎn)數(shù) 當(dāng)相鄰多段軌跡線段的端點(diǎn)兩兩之間距離均小于給定的時(shí)間長(zhǎng)度時(shí)，將其合并（僅保留起點(diǎn)和終點(diǎn)）。
drop_point.period_lesser 可以轉(zhuǎn)化為Interval類型的字符串 當(dāng)相鄰多段軌跡線段的時(shí)間長(zhǎng)度之和小于給定的時(shí)間長(zhǎng)度時(shí)，將其合并（僅保留起點(diǎn)和終點(diǎn)）。

描述

根據(jù)提前設(shè)定的規(guī)則切分軌跡對(duì)象，返回切分后的子軌跡數(shù)組。

示例

SELECT ST_Resample(ST_MakeTrajectory('POINT(1 1)'), '{"add_point.distance_lesser":3}');
                                                                                        st_resample
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 {"trajectory":{"version":1,"type":"STPOINT","leafcount":1,"start_time":"2000-01-01 00:00:00","end_time":"2000-01-01 00:00:00","spatial":"POINT(1 1)","timeline":["2000-01-01 00:00:00"]}}
(1 row)

SELECT ST_Resample(ST_MakeTrajectory('POINT(1 1)'), '{"add_point.period_lesser":"2 day"}');
                                                                                        st_resample
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 {"trajectory":{"version":1,"type":"STPOINT","leafcount":1,"start_time":"2000-01-01 00:00:00","end_time":"2000-01-01 00:00:00","spatial":"POINT(1 1)","timeline":["2000-01-01 00:00:00"]}}
(1 row)

SELECT ST_Resample(ST_MakeTrajectory('POINT(1 1)'), '{"drop_point.distance_lesser":3}');
                                                                                        st_resample
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 {"trajectory":{"version":1,"type":"STPOINT","leafcount":1,"start_time":"2000-01-01 00:00:00","end_time":"2000-01-01 00:00:00","spatial":"POINT(1 1)","timeline":["2000-01-01 00:00:00"]}}
(1 row)