准備一個線shp數據，並將其導入postgres里面，postgres安裝postgis和pgrouting兩個插件（方法見http://www.cnblogs.com/nidaye/p/4553522.html）。線數據的字段如下：注意字段的名稱，省的出現不必要的麻煩。
1、ALTER TABLE beijing_line ADD COLUMN source integer;
ALTER TABLE beijing_line ADD COLUMN target integer;
ALTER TABLE beijing_line ADD COLUMN length double precision;
UPDATE beijing_line SET length = ST_Length(the_geom);
ps：執行createTopology這個函數之前一定得對數據庫執行以下三句sql查詢：
CREATE EXTENSION postgis;
CREATE EXTENSION postgis_topology;
CREATE EXTENSION fuzzystrmatch;
2、select pgr_createTopology('beijing_line',0.001,source:='source',id:='gid',target:='target',the_geom:='the_geom');
select pgr_createTopology('beijing_line',0.1,source:='source',id:='gid',target:='target',the_geom:='the_geom’);
把容差值設置的大一點，可能結果會好點
3、 SELECT * FROM pgr_dijkstra('
SELECT gid as id,
source::integer,
target::integer,
length::double precision as cost
FROM beijing_line',
30, 60, false, false);
無查詢結果就執行下面這幾個試一試，也可能是兩點之間就沒有路徑
select source from beijing_line;
select target from beijing_line;
select length from beijing_line;
4、查詢所經過的所有點：
SELECT st_astext(the_geom) FROM pgr_dijkstra('
SELECT gid AS id,
source::integer,
target::integer,
length::double precision AS cost
FROM beijing_line',
30, 60, false, false) as di
join beijing_line pt
on di.id2 = pt.gid;
5、將路徑寫入一個幾何文件內：
SELECT seq, id1 AS node, id2 AS edge, cost,the_geom into dijkstra_res FROM pgr_dijkstra('
SELECT gid AS id,
source::integer,
target::integer,
length::double precision AS cost
FROM beijing_line',
30, 60, false, false) as di
join beijing_line pt
on di.id2 = pt.gid;
經歷過以上的步驟，如果一切順利，應該能看到結果，這里不再截圖。這時初步的准備工作已經完成。
參考博文如下（）：
2、pgrouting進行路徑規划之入門二（1和2是一個求最短路徑博文系列，挺不錯的可以看看，但可能是因為機器配置環境的不同，原封不動的可能無法運行別人的代碼，一定搞懂原理，然后可對前人的代碼改進）