postgressql+geoserver實現路徑分析

總體思路是用geoserver發佈圖層，圖層爲 sql，視圖是利用存儲過程分析出的路徑結果，

shp導入數據庫

路網通常爲shp數據，若是有多個圖層，建議利用arcgis或其餘工具合併爲一個圖層，方便處理

數據庫空間擴展

使用paAdmin3鏈接PostgreSQL，並執行如下語句，在新的空間數據庫裏添加空間擴展：

CREATE EXTENSION postgis;
CREATE EXTENSION pgrouting;
CREATE EXTENSION postgis_topology;
CREATE EXTENSION fuzzystrmatch;
CREATE EXTENSION postgis_tiger_geocoder;
CREATE EXTENSION address_standardizer;

使用shp2pgsql-gui.exe導入

添加路網數據，設置表名，並設置SRID爲：4326
須要使用GBK編碼，並勾選最下面一個選項。

表結構進行修改

1.修改表結構

--添加起點id
ALTER TABLE lproad ADD COLUMN source integer;

--添加終點id
ALTER TABLE lproad  ADD COLUMN target integer;

--添加道路權重值
ALTER TABLE lproad  ADD COLUMN length double precision

2.建立拓撲結構　　　　　　　　　　　　　　　　　　

--爲lproad表建立拓撲佈局，即爲source和target字段賦值
SELECT pgr_createTopology('lproad ',0.0001, 'geom', 'gid');

3.建立索引

--爲source和target字段建立索引
CREATE INDEX source_idx ON lproad ("source");
CREATE INDEX target_idx ON lproad ("target");

4.給長度賦值

--爲length賦值
update lproad set length =st_length(geom);

--爲lproad 表添加reverse_cost字段並用length的值賦值
ALTER TABLE lproad ADD COLUMN reverse_cost double precision;
UPDATE lproad SET reverse_cost =length;

建立最短路徑函數

-- DROP FUNCTION public.pgr_fromatoe(double precision, double precision, double precision, double precision);
 
CREATE OR REPLACE FUNCTION pgr_fromatoe(
    tbl varchar,
    startx double precision,
    starty double precision,
    endx double precision,
    endy double precision)
    RETURNS geometry
    LANGUAGE 'plpgsql'
 
    COST 100
    VOLATILE STRICT 
AS $BODY$
    
declare   
    v_startLine geometry;--離起點最近的線   
    v_endLine geometry;--離終點最近的線   
    v_startTarget integer;--距離起點最近線的終點   
    v_startSource integer;   
    v_endSource integer;--距離終點最近線的起點    
    v_endTarget integer;    
    v_statpoint geometry;--在v_startLine上距離起點最近的點   
    v_endpoint geometry;--在v_endLine上距離終點最近的點   
    v_res geometry;--最短路徑分析結果 
    
    v_res_a geometry;  
    v_res_b geometry;  
    v_res_c geometry;  
    v_res_d geometry;
    
    v_start_temp geometry;
    v_start_temp1 geometry;
    v_start_temp2 geometry;
    v_end_temp geometry;
    v_end_temp1 geometry;
    v_end_temp2 geometry;
  
    v_perStart float;--v_statpoint在v_res上的百分比   
    v_perEnd float;--v_endpoint在v_res上的百分比   
  
    v_shPath_se geometry;--開始到結束  
    v_shPath_es geometry;--結束到開始  
    v_shPath geometry;--最終結果  
  
    tempnode float;    
      
    startpoint geometry;  
    endpoint geometry;  
  
    v_shPath1 geometry;--一次結果  
    v_shPath2 geometry;--二次結果  
    star_line geometry; --起點到最近點的線  
    end_line geometry; --終點到最近點的線  
    geoARR geometry[];  
  
begin  
  
    --查詢離起點最近的線   
    --4326座標系  
    --找起點15米範圍內的最近線  
  
    execute 'select geom, source, target  from  '|| tbl ||
        ' where ST_DWithin(geom,ST_Geometryfromtext(''point('|| startx ||' ' || starty||')'',4326),3000)  
         order by ST_Distance(geom,ST_GeometryFromText(''point('|| startx ||' '|| starty ||')'',4326))  limit 1'  
        into v_startLine, v_startSource ,v_startTarget;   
  
raise notice '%',  v_startSource;  
raise notice '%', v_startTarget;  
  
    --查詢離終點最近的線   
    --找終點15米範圍內的最近線  
  
    execute 'select geom, source, target from '|| tbl || 
        ' where ST_DWithin(geom,ST_Geometryfromtext(''point('|| endx || ' ' || endy ||')'',4326),3000)    
        order by ST_Distance(geom,ST_GeometryFromText(''point('|| endx ||' ' || endy ||')'',4326))  limit 1'   
        into v_endLine, v_endSource,v_endTarget;   
raise notice '%',  v_endSource;  
raise notice '%', v_endTarget;  
   
    --若是沒找到最近的線，就返回null    
    if (v_startLine is null) or (v_endLine is null) then     
        return null;     
    end if ;   
  
    select  ST_ClosestPoint(v_startLine, ST_Geometryfromtext('point('|| startx ||' ' || starty ||')',4326)) into v_statpoint;     
    select  ST_ClosestPoint(v_endLine, ST_GeometryFromText('point('|| endx ||' ' || endy ||')',4326)) into v_endpoint;   
  
   -- ST_Distance   
  
    --從開始的起點到結束的起點最短路徑  
  
    execute 'SELECT st_linemerge(st_union(b.geom)) ' ||  
    'FROM pgr_kdijkstraPath(   
    ''SELECT gid as id, source, target, length as cost FROM '|| tbl ||' '','   
    ||v_startSource || ', ' ||'array['||v_endSource||'] , false, false   
    ) a, lproad b   
    WHERE a.id3=b.gid     
    GROUP by id1     
    ORDER by id1' into v_res ;  
  
    --從開始的終點到結束的起點最短路徑  
  
    execute 'SELECT st_linemerge(st_union(b.geom)) ' ||    
    'FROM pgr_kdijkstraPath(    
    ''SELECT gid as id, source, target, length as cost FROM '|| tbl ||' '','    
    ||v_startTarget || ', ' ||'array['||v_endSource||'] , false, false     
    ) a, lproad b     
    WHERE a.id3=b.gid    
    GROUP by id1      
    ORDER by id1' into v_res_b ;     
  
    --從開始的起點到結束的終點最短路徑  
  
    execute 'SELECT st_linemerge(st_union(b.geom)) ' ||   
    'FROM pgr_kdijkstraPath(    
    ''SELECT gid as id, source, target, length as cost FROM '|| tbl ||' '','    
    ||v_startSource || ', ' ||'array['||v_endTarget||'] , false, false    
    ) a, lproad b    
    WHERE a.id3=b.gid       
    GROUP by id1       
    ORDER by id1' into v_res_c ;   
  
    --從開始的終點到結束的終點最短路徑  
  
    execute 'SELECT st_linemerge(st_union(b.geom)) ' ||    
    'FROM pgr_kdijkstraPath(     
    ''SELECT gid as id, source, target, length as cost FROM '|| tbl ||' '','     
    ||v_startTarget || ', ' ||'array['||v_endTarget||'] , false, false     
    ) a, lproad b     
    WHERE a.id3=b.gid    
    GROUP by id1       
    ORDER by id1' into v_res_d ;  
                                                           
    if(ST_Length(v_res) > ST_Length(v_res_b)) then  
       v_res = v_res_b;  
    end if;  
                                    
    if(ST_Length(v_res) > ST_Length(v_res_c)) then  
       v_res = v_res_c;  
    end if;       
  
    if(ST_Length(v_res) > ST_Length(v_res_d)) then  
       v_res = v_res_d;  
    end if;  
  
    --若是找不到最短路徑，就返回null   
  
    if(v_res is null) then   
        return null;   
    end if;   
   
    --將v_res,v_startLine,v_endLine進行拼接   
  
    --select  st_linemerge(ST_Union(array[v_startLine,v_res,v_endLine])) into v_res;  
  
     select  ST_LineLocatePoint(v_startLine, v_statpoint) into v_perStart; 
     select  ST_LineLocatePoint(v_endLine, v_endpoint) into v_perEnd;
     
     SELECT ST_Line_SubString(v_startLine,v_perStart, 1) into v_start_temp1;
     SELECT ST_Line_SubString(v_startLine,0,v_perStart) into v_start_temp2;
     
     SELECT ST_Line_SubString(v_endLine,v_perEnd, 1) into v_end_temp1;
     SELECT ST_Line_SubString(v_endLine,0,v_perEnd) into v_end_temp2;
     
     raise notice '%',  v_perStart;  
     raise notice '%', v_perEnd;
     
     raise notice '%', ST_Distance(v_res,v_start_temp1);
     raise notice '%', ST_Distance(v_res,v_start_temp2);
     raise notice '%', ST_Distance(v_res,v_end_temp2);
     raise notice '%', ST_Distance(v_res,v_end_temp1);
     
     v_start_temp=v_start_temp1;
     if(ST_Distance(v_res,v_start_temp1) > ST_Distance(v_res,v_start_temp2)) then   
      v_start_temp=v_start_temp2; 
    end if;  
     v_end_temp=v_end_temp1;
     if(ST_Distance(v_res,v_end_temp1) > ST_Distance(v_res,v_end_temp2)) then   
      v_end_temp=v_end_temp2; 
    end if;  
    --return ST_AsGeoJSON(v_res); 
    --return v_res;
                                                     
   -- select  ST_LineLocatePoint(v_res, v_statpoint) into v_perStart;   
   -- select  ST_LineLocatePoint(v_res, v_endpoint) into v_perEnd;   
  
    --if(v_perStart > v_perEnd) then   
    --    tempnode =  v_perStart;  
    --   v_perStart = v_perEnd;  
    --    v_perEnd = tempnode;  
  
    --end if;  
  
    --截取v_res   
    --拼接線  
  
    --SELECT ST_Line_SubString(v_res,v_perStart, v_perEnd) into v_shPath1; 
    select  st_linemerge(ST_Union(array[v_start_temp,v_res,v_end_temp])) into v_shPath1;
                                        
    return v_shPath1; 
  
 --後續爲將起點終點與路網鏈接起來，因發佈時有點問題，暫不使用 
 --找線的端點  
 select ST_SetSRID( ST_MakePoint(startx , starty),4326 )into startpoint;  
 select ST_SetSRID( ST_MakePoint(endx , endy),4326 )into endpoint;  
 select ST_MakeLine( v_statpoint,startpoint) into star_line;   
 select ST_MakeLine( v_endpoint,endpoint) into end_line;    
 
geoARR :=array[end_line,v_shPath1,star_line];  
select st_union(geoARR) into v_shPath;  
   
   raise notice '%', '返回數據';  
   --raise notice '%', ST_AsGeoJSON(v_shPath);
    
    return v_shPath; 

end;  
                                        
$BODY$;

數據發佈

數據準備完成後，就須要用GeoServer來進行發佈：

啓動GeoServer，在瀏覽器中輸入，http://localhost:8080/geoserver/web/，登陸到GeoServer。

1.建立工做區

2.添加數據存儲

配置數據庫鏈接

3.添加圖層

選擇「配置新的SQL視圖」，輸入SQL語句：

SELECT * FROM pgr_fromAtoB('road_xblk', %x1%, %y1%, %x2%, %y2%)

驗證的正則表達式：^-?[d.]+$

類型：LingString

SRID：4326

點擊保存後，填入SRS，並自動計算範圍

結果展現

一、wms方式加載

var viewparams = [
  'x1:' + startCoord[0], 'y1:' + startCoord[1],
  'x2:' + destCoord[0], 'y2:' + destCoord[1] 
];
params.viewparams = viewparams.join(';'); 
result = new ol.layer.Image({
  source: new ol.source.ImageWMS({
    url: ServerUrl + '/geoserver/Routing/wms',
    params: params
  })
}); 
map.addLayer(result);

二、wfs方式加載

var vectorSource = new ol.source.Vector({
  format: new ol.format.GeoJSON(),
  url: function (extent) {
    return ServerUrl + '/geoserver/wfs?service=WFS&' + 
    'version=1.1.0&request=GetFeature&typename=Routing:lproute&' +
    'outputFormat=application/json&srsname=EPSG:4326&' + 
    'bbox=' + extent.join(',') + ',EPSG:4326&' +
    'viewparams=' + viewparams.join(';');
  },
  strategy: ol.loadingstrategy.bbox
}); 
var vector = new ol.layer.Vector({
  source: vectorSource, 
}); 
map.addLayer(vector);

三、直接請求服務

var wfsurl = ServerUrl + '/geoserver/wfs?service=WFS&' +
  'version=1.1.0&request=GetFeature&typename=Routing:lproute&' +
  'outputFormat=application/json&srsname=EPSG:4326&' +
  'viewparams=' + viewparams.join(';');
$.ajax({
  url: wfsurl,
  success: function (result) {
    console.log(result);
  }
});

效果如圖：