用pgrouting对openstreetmap数据进行路径分析

1，将道路osm数据增加列字段

ALTER TABLE changsharoad_connected ADD COLUMN source integer;

ALTER TABLE changsharoad_connected ADD COLUMN target integer;

ALTER TABLE changsharoad_connected ADD COLUMN length double precision;

ALTER TABLE changsharoad_connected ADD COLUMN cost double precision;

ALTER TABLE changsharoad_connected ADD COLUMN reverse_cost double precision;

2，创建拓扑及索引
SELECT pgr_createTopology('changsharoad_connected',0.000001, 'geom', 'gid');

create index road_source_idx on changsharoad_connected("source");

create index road_target_idx on changsharoad_connected("target");

3，分析单双向
SELECT pgr_analyzeOneway('changsharoad_connected', ARRAY['', 'B', 'T'], ARRAY['', 'B', 'F'],ARRAY['', 'B', 'F'], ARRAY['', 'B', 'T'])

update changsharoad_connected set length = ST_LengthSpheroid(geom, 'SPHEROID["WGS 84",6378137,298.257223563]');

update changsharoad_connected set cost=length where oneway='B' or oneway='F'

update changsharoad_connected set cost=-length where oneway='T'

update changsharoad_connected set reverse_cost=-length where oneway='F'

update changsharoad_connected set reverse_cost=length where oneway='B' or oneway='T'

4，最短路径分析
drop table if exists dijkstra_res;

SELECT seq, id1 AS node, id2 AS edge, a.cost as cost, geom into dijkstra_res FROM pgr_dijkstra('     

    SELECT gid AS id,

        source::integer,

        target::integer,

        cost::double precision AS cost,

        reverse_cost::double precision AS reverse_cost

    FROM changsharoad_connected', 20946, 19758, true, true)a

LEFT JOIN changsharoad_connected b

ON (a.id2 = b.gid) order by seq;