这个算法算是被摒弃了，但是很多自己思考过后留下的成果，虽然不用了，留着做记录。
算法目的是为了发生爆管后找到总阀门，这里分了几个步骤：
1、找到爆管点所在管段
2、通过遍历找到爆管点所有影响的阀门
3、找到影响阀门中的上游阀门
4、在上游阀门中进行遍历，看相互关系，与其他阀门都联通的则视为总阀门
5、找出阀门中的总阀门
#考虑了一下，所有与爆点相连的上游阀门其实在爆管发生后都需要关闭。所以算法中4、5步，不需要了。
-- Function: test_getpoint7(character varying, double precision, double precision)
-- DROP FUNCTION test_getpoint7(character varying, double precision, double precision);
CREATE OR REPLACE FUNCTION test_getpoint7(
IN tbl character varying,
IN startx double precision,
IN starty double precision)
RETURNS TABLE(v_gid integer, v_res geometry, v_type integer) AS
$BODY$ declare
v_startLine geometry;--离起点最近的线
v_startTarget integer;--距离起点最近线的终点
v_startSource integer;
v_statpoint geometry;--在v_startLine上距离起点最近的点
v_endpoint geometry;--在v_endLine上距离终点最近的点
v_up_source integer;--游标，记录是否有记录
v_up_idx integer;--记录遍历到多少层级
v_uptap_gid integer;--上游阀门gid
v_uptap_geom geometry;--上游阀门要素
v_all_where integer[];--记录所有查询过的管段
v_up_where integer[];--where条件，将遍历到阀门的管段gid排除
v_down_where integer[];--where条件，将遍历到阀门的管段gid排除
up_temprow record ;
--v_cost record;--记录阀门管段source（用于计算消耗，判断方向）
m_cost integer;
m_cost_value integer;
temprow record;
v_cost integer[];
res_source integer;
res_tap_pipe text[];
m_tap_pipe text;
idx_tap_pipe integer; --遍历结果游标
m_up_cost integer;--上游阀门
v_up_cost integer[];--上游阀门集合
res_main_pipe integer[];--总阀门集合
m_main_pipe integer;--总阀门
begin
--查询离起点最近的线
--3857坐标系
--找起点15米范围内的最近线
execute 'select geom, source, target, ST_StartPoint(geom) as startpoint,ST_EndPoint(geom) as endpoint from ' ||tbl||
' where ST_DWithin(geom,ST_Geometryfromtext(''point('|| startx ||' ' || starty ||')'',3857),15)
order by ST_Distance(geom,ST_GeometryFromText(''point('|| startx ||' '|| starty ||')'',3857)) limit 1'
into v_startLine, v_startSource ,v_startTarget, v_statpoint ,v_endpoint;
IF(v_startLine is not null) THEN
--查找上游阀门
v_up_idx = 0;
v_up_source = 1;
--寻找上游阀门
SELECT array_append(v_up_where, v_startSource) into v_up_where;
--如果没有下级节点需要遍历
WHILE array_length(v_up_where,1) > 0
LOOP
--游标归零
v_up_source = 0;
--记录层级
v_up_idx = v_up_idx + 1;
--获取当前层级节点
FOR up_temprow IN
select zy1.gid,zy1.source,zy1.target from zy zy1 where source = any(v_up_where) or target = any(v_up_where)
--select zy1.gid,zy1.source,zy1.target from zy zy1 where target = any(v_up_where)--找上游
LOOP
--清空需要查的点
IF(v_up_source = 0) THEN
v_up_where = null;
END IF;
--清空初始执行节点
v_startSource = 0;
--标志执行有数据
v_up_source = 1;
--查询管网上的点
select t.gid,t.geom from fm t where t.gid in (
select a.gid from fm a,(select c.* from zy c where c.gid = up_temprow.gid) b where ST_intersects(a.geom,b.geom)
) into v_uptap_gid, v_uptap_geom;
raise notice '%' , 'UP---'||up_temprow.gid;
--如果没查找到阀门，则继续往下查
IF(v_uptap_gid is null) then
--source去重，判断如果数组中已有，则不添加
IF (v_up_where @> ARRAY[up_temprow.source::integer] OR v_all_where @> ARRAY[up_temprow.source::integer]) THEN
ELSE
SELECT array_append(v_up_where,up_temprow.source) into v_up_where;
SELECT array_append(v_all_where,up_temprow.source) into v_all_where;
END IF;
--target去重，判断如果数组中已有，则不添加
IF (v_up_where @> ARRAY[up_temprow.target::integer] OR v_all_where @> ARRAY[up_temprow.target::integer]) THEN
ELSE
SELECT array_append(v_up_where,up_temprow.target) into v_up_where;
SELECT array_append(v_all_where,up_temprow.target) into v_all_where;
END IF;
ELSE
raise notice '%' , up_temprow.source;
--记录阀门所在管段source
IF (v_cost @> ARRAY[up_temprow.source::integer]) THEN
ELSE
SELECT array_append(v_cost,up_temprow.source) into v_cost;
SELECT array_append(v_cost,up_temprow.target) into v_cost;
END IF;
--insert into v_cost values (up_temprow.gid,up_temprow.source,v_uptap_gid,v_uptap_geom );
--insert into v_cost values (up_temprow.gid,up_temprow.target,v_uptap_gid,v_uptap_geom );
--insert into v_cost values (up_temprow.gid,v_uptap_geom ,v_uptap_gid);
--return next v_cost;
--insert into v_taps values (v_uptap_gid, v_uptap_geom, up_temprow.source);
--v_cost = up_temprow;
--执行返回结果
--阀门id，阀门图形要素，阀门类型（上游/下游）
--return query
--select v_uptap_gid as res_uptap_gid,v_uptap_geom as res_uptap_geom ,up_temprow.source as res_source;
--raise notice '%' , 'res_tap_pipe---'||cast(res_tap_pipe as text);
IF (res_tap_pipe is not null) THEN
--SELECT array_append(res_tap_pipe,ARRAY[v_uptap_gid,up_temprow.source]) into res_tap_pipe;
--select cast(res_tap_pipe as text);
select res_tap_pipe || ARRAY[v_uptap_gid||','||cast(v_uptap_geom as text)||','||up_temprow.source] into res_tap_pipe;
ELSE
select ARRAY[v_uptap_gid||','||cast(v_uptap_geom as text)||','||up_temprow.source] into res_tap_pipe;
END IF;
END IF;
--return next;
END LOOP;
END LOOP;
--raise notice '%' , v_cost;
raise notice '%' , 'res_tap_pipe---'||cast(res_tap_pipe as text);
--return query select * from v_cost;
raise notice '%' , 'v_cost---'||cast(v_cost as text); --查找上游阀门
FOREACH m_cost IN ARRAY v_cost
LOOP
SELECT count(*) FROM pgr_dijkstraCost('select gid as id, source, target, length as cost, reverse_cost from zy',m_cost, ARRAY[v_startSource,v_startTarget], true) where agg_cost >= 9999999 into m_cost_value;
raise notice '%' , 'm_cost_value---'||cast(m_cost_value as text);
--如果没有消耗大于9999999的（阈值），则认为是上游阀门
IF(m_cost_value = 0) THEN
--判断上游阀门间是否有上下游关系
SELECT array_append(v_up_cost,m_cost) into v_up_cost;
END IF;
--IF(m_cost_value = array_length(v_cost,1)/2 - 1) THEN
----return query
---- select * from v_taps where source = m_cost;
----raise notice '%' , 'res_tap_pipe---'||cast(unnest(res_tap_pipe) as text);
--FOREACH m_tap_pipe IN ARRAY res_tap_pipe
--LOOP
--raise notice '%' , 'm_cost---'||cast(m_cost as text) ;
--IF (split_part(m_tap_pipe, ',', 3)::integer = m_cost) THEN
----阀门id，阀门图形要素，阀门类型（上游/下游）
--return query
--select split_part(m_tap_pipe, ',', 1)::integer as res_uptap_gid,split_part(m_tap_pipe, ',', 2)::geometry as res_uptap_geom ,split_part(m_tap_pipe, ',', 3)::integer as res_source;
--END IF;
--idx_tap_pipe = idx_tap_pipe+1;
--END LOOP;
--END IF;
END LOOP; raise notice '%' , '上游阀门---'||cast(v_up_cost as text); --循环遍历找主阀门
FOREACH m_up_cost IN ARRAY v_up_cost
LOOP
SELECT count(*) FROM pgr_dijkstraCost('select gid as id, source, target, length as cost, reverse_cost from zy',m_up_cost, v_up_cost, true) where agg_cost >= 9999999 into m_cost_value;
IF(m_cost_value = 0) THEN
SELECT array_append(res_main_pipe,m_up_cost) into res_main_pipe;
END IF;
END LOOP; raise notice '%' , 'res_main_pipe---'||cast(res_main_pipe as text); IF(res_main_pipe IS NULL OR array_length(res_main_pipe,1)=0) THEN
res_main_pipe = v_up_cost;
END IF; FOREACH m_main_pipe IN ARRAY res_main_pipe
LOOP
FOREACH m_tap_pipe IN ARRAY res_tap_pipe
LOOP
raise notice '%' , 'm_cost---'||cast(m_cost as text) ;
IF (split_part(m_tap_pipe, ',', 3)::integer = m_main_pipe) THEN
--阀门id，阀门图形要素，阀门类型（上游/下游）
return query
select split_part(m_tap_pipe, ',', 1)::integer as res_uptap_gid,split_part(m_tap_pipe, ',', 2)::geometry as res_uptap_geom ,split_part(m_tap_pipe, ',', 3)::integer as res_source;
END IF;
END LOOP;
END LOOP;
END IF;
--查找总阀门 --FOR temprow IN -- select * from v_cost --LOOP -- SELECT count(*) FROM pgr_dijkstraCost('select gid as id, source, target, length as cost, reverse_cost from zy',m_cost, v_cost, true) where agg_cost <9999999 into m_cost_value; -- if(m_cost_value == ) --END LOOP;
end;
$BODY$
LANGUAGE plpgsql VOLATILE STRICT
COST 100
ROWS 1000;
ALTER FUNCTION test_getpoint7(character varying, double precision, double precision)
OWNER TO postgres;
