Question

我有一个包含（样本）的表samplecol：

vessel_hash  | status | station | speed |  latitude   |  longitude  | course | heading |        timestamp         |                      the_geom                      
--------------+--------+---------+-------+-------------+-------------+--------+---------+--------------------------+----------------------------------------------------
 103079215239 | 99     | 841     | 5     | -5.41844510 | 36.12160900 | 314    | 511     | 2016-06-12T06:31:04.000Z | 0101000020E61000001BF33AE2900F424090AF4EDF7CAC15C0
 103079215239 | 99     | 3008    | 0     | -5.41778710 | 36.12144900 | 117    | 511     | 2016-06-12T06:43:27.000Z | 0101000020E6100000E2900DA48B0F424042C3AC61D0AB15C0
 103079215239 | 99     | 841     | 17    | -5.42236900 | 36.12356900 | 259    | 511     | 2016-06-12T06:50:27.000Z | 0101000020E610000054E6E61BD10F42407C60C77F81B015C0
 103079215239 | 99     | 841     | 17    | -5.41781710 | 36.12147900 | 230    | 511     | 2016-06-12T06:27:03.000Z | 0101000020E61000004D13B69F8C0F424097D6F03ED8AB15C0
 103079215239 | 99     | 841     | 61    | -5.42201900 | 36.13256100 | 157    | 511     | 2016-06-12T06:08:04.000Z | 0101000020E6100000CFDC43C2F71042409929ADBF25B015C0
 103079215239 | 99     | 841     | 9     | -5.41834020 | 36.12225000 | 359    | 511     | 2016-06-12T06:33:03.000Z | 0101000020E6100000CFF753E3A50F42408D68965F61AC15C0

我尝试使用：

获取多边形内的所有点

poisInpolygon = """SELECT col.vessel_hash,col.longitude,col.latitude,
            ST_Contains(ST_GeomFromEWKT('SRID=4326; POLYGON((-15.0292969 47.6357836,-15.2050781 47.5172007,-16.2597656 29.3821751, 35.0683594 26.1159859, 38.0566406 47.6357836,-15.0292969 47.6357836))'),
            ST_GeomFromEWKT(col.the_geom)) FROM samplecol As col;"""

输出结果为：

(103079215291L, Decimal('40.87123100'), Decimal('29.24107000'), False) 

(103079215291L, Decimal('40.86702000'), Decimal('29.23967000'), False) 

(103079215291L, Decimal('40.87208200'), Decimal('29.22113000'), False) 

(103079215291L, Decimal('40.86973200'), Decimal('29.23963000'), False) 

(103079215291L, Decimal('40.87770800'), Decimal('29.20229900'), False)

我不知道结果中的False是多少。这是正确的方法，还是我做错了什么？

此代码还使用字段the_geom中的INDEX？

Answer 1

查询返回false，因为样本中的所有点都在给定多边形之外。这里概述了你的观点（在坦桑尼亚东北部的某个地方）和多边形（南欧和北非）：

为了测试你的查询，我在Málaga中的某个位置添加了另一个点，它位于多边形内部，并且正如预期的那样返回true（插入语句中的最后几何体为EWKT）。这是脚本：

CREATE TEMPORARY TABLE t (the_geom GEOMETRY);
INSERT INTO t VALUES ('0101000020E61000001BF33AE2900F424090AF4EDF7CAC15C0'),
             ('0101000020E6100000E2900DA48B0F424042C3AC61D0AB15C0'),
             ('0101000020E610000054E6E61BD10F42407C60C77F81B015C0'),
             ('0101000020E61000004D13B69F8C0F424097D6F03ED8AB15C0'),
             ('0101000020E6100000CFDC43C2F71042409929ADBF25B015C0'),
             ('0101000020E6100000CFF753E3A50F42408D68965F61AC15C0'),
             (ST_GeomFromEWKT('SRID=4326;POINT(-4.4427 36.7233)'));

以下是您的查询：

db=# SELECT 
ST_Contains(ST_GeomFromEWKT('SRID=4326; POLYGON((-15.0292969 47.6357836,-15.2050781 47.5172007,-16.2597656 29.3821751, 35.0683594 26.1159859, 38.0566406 47.6357836,-15.0292969 47.6357836))'),
            ST_GeomFromEWKT(col.the_geom)) 
FROM t As col;

st_contains 
-------------
 f
 f
 f
 f
 f
 f
 t
(7 Zeilen)

顺便说一下：存储与GEOMETRY和NUMERIC相同的坐标是完全多余的。您可能希望删除列latitude和longitude，并根据需要使用ST_X和ST_Y提取其值。

PostGIS

1 个答案: