基于postgis时空查询-记录而已

所有道路的总长度是多少（以公里为单位）？先设置空间坐标系，然后利用投影坐标系转换

select UpdateGeometrySRID('road_table', 'osm_geom', 4326);

SELECT sum(ST_Length(ST_Transform(osm_geom,2436)))/1000 AS km_roads from road_table;

空间查询更有效

SELECT geom as result_out FROM node_table WHERE ST_DWithin(geom, 'POINT(116.3211279 39.984223)', 0.002);

操作查询结果

SELECT ST_DWithin(geom, 'SRID=0;POINT(116.3211279 39.984223)', 0.0015) as result_bool FROM node_table WHERE ST_DWithin(geom, 'SRID=0;POINT(116.3211279 39.984223)', 0.002);

多条件查询—空间查询

SELECT geom as result_bool FROM node_table WHERE ST_DWithin(geom, 'SRID=0;POINT(116.3211279 39.984223)', 0.002) and ST_DWithin(geom, ' SRID=0;POINT(116.3211279 39.984223)', 0.0015);

多条件查询--时间范围查询

SELECT geom FROM node_table where tstamp < '2021-03-15 21:45:46' and '2021-03-15 21:45:43' < tstamp;

多条件查询—时空查询

select

    ST_DWithin(time_result.geom, 'SRID=0;POINT(116.3211279 39.984223)', 0.002) as result_bool

from (

    select

       node_id, name, geom

    from node_table

    WHERE node_table.tstamp < '2021-03-15 21:45:46' and '2021-03-15 21:45:43' < node_table.tstamp

) as time_result;

多条件查询—时空查询--最佳 给定经纬度+度数阈值（存储默时没社坐标系，即没有SRID）

select

    node_id, name, geom

from node_table

WHERE node_table.tstamp < '2021-03-15 21:45:46' and '2021-03-15 21:45:43' < node_table.tstamp and ST_DWithin(node_table.geom, 'SRID=0;POINT(116.3211279 39.984223)', 0.0002)

多条件查询—时空查询--最佳 给定经纬度+距离阈值

select UpdateGeometrySRID('node_table', 'geom', 4326);

select

    node_id, name, geom

from node_table

WHERE node_table.tstamp < '2021-03-15 21:45:46' and '2021-03-15 21:45:43' < node_table.tstamp

    and ST_DWithin(ST_Transform(node_table.geom,2436), ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(116.3211279 39.984223)'),2436), 265.5);

用到了坐标转换ST_Transform

ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(116.3211279 39.984223)'),2436)

ST_Transform(geom,2436)

空间查询--给定经纬度+距离阈值

select

    node_id, name, geom

from node_table

WHERE ST_DWithin(ST_Transform(node_table.geom,2436), ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(116.3211279 39.984223)'),2436), 365.5);

坐标系SRID1为：2249（投影坐标系）；坐标系SRID2为：4326（地理坐标系）。