如何選擇一條線附近的所有點？

我有一個線串：如何選擇一條線附近的所有點？

LINESTRING(-43.0965167 -22.8808585,-43.0980368 -22.8807975,-43.0986518 
-22.8807735,-43.0990955 -22.8807701,-43.0991492 -22.8807697,-43.1005956 
-22.8807353,-43.1013221 -22.8807107,-43.1016904 -22.8807003,-43.1019484 
-22.8806902,-43.1020398 -22.8806866,-43.102591 -22.8806801,-43.1029336 
-22.8806666,-43.1036051 -22.8806402,-43.1039349 -22.8806272,-43.1042967 
-22.880613,-43.1061912 -22.8805398)

現在我可以從該行的距離「X」（圍繞線）選擇所有點。我已經嘗試Find the nearest points along the linestring in specified distance limit and order沒有成功（總是在像分發這樣的盒子裏拿很多分）。這是一段代碼，我開始寫：

select p.way,p.name from planet_osm_point p where ST_DWithin( 
    ST_Transform(theLineGeom, 4326), ST_Transform(p.way,4326), 0.9) 
    limit 50;

來源

2017-02-14 Magno C

我覺得你得到很多分，因爲ST_DWithin使用幾何SRID爲單位進行計算。

布爾值ST_DWithin（幾何g1，幾何g2，雙精度distance_of_srid）;

所以，你得到了你的線串0.9度的所有點。

你可以使用

布爾ST_DWithin（地理GG1，GG2地理，雙精度DISTANCE_METERS）;

將您的幾何體轉換爲地理區域。

否則你可以使用另一個srid。

來源

2017-02-15 10:55:56 fradal83

已解決。我只是得到太多分，因爲限制太大。如果我在路線附近有2個點並告訴查詢給我第50個點，那麼48個點將遠離線，但在邊界框內。這就是我看到box like distribution的原因。

select * from pointscanner('<geomRoute_WILL_BE_HERE>') where round(distance::numeric, 5) < 500 /* meters */

CREATE OR REPLACE FUNCTION public.pointscanner(IN routeGeometry text) 
    RETURNS TABLE(way geometry, name text, distance double precision, tags hstore, operator text, admin_level text, z_order integer) AS 
$BODY$ 
DECLARE 
    geomRoute geometry; 
    routeBB box2d; 
BEGIN 
    geomRoute = ST_GeomFromText('MULTILINESTRING( 
     (-43.1761935 -22.90642,-43.1755606 -22.9064116,-43.1754828 -22.9064106,-43.1753675 -22.9064091), 
     (-43.176696 -22.9064062,-43.1761935 -22.90642),(-43.176805 -22.9064027,-43.176696 -22.9064062), 
     (-43.1776911 -22.9049927,-43.1776625 -22.9050849,-43.1775227 -22.9055527,-43.1775045 -22.9056041,-43.1774504 -22.9057582), 
     (-43.1782012 -22.9036858,-43.1778613 -22.9045254,-43.1777841 -22.9047287,-43.1777446 -22.9048326,-43.1777179 -22.9049164,-43.1776911 -22.9049927), 
     (-43.1772218 -22.9063929,-43.1771252 -22.9063944,-43.1771118 -22.9063946,-43.1769202 -22.9064008,-43.176805 -22.9064027), 
     (-43.1774504 -22.9057582,-43.1773182 -22.9061373,-43.1772868 -22.9062205,-43.1772218 -22.9063929), 
     (-43.1834587 -22.9028997,-43.1833984 -22.9028862,-43.1830022 -22.9027778,-43.1825446 -22.9026278,-43.1821151 -22.9024891,-43.1816491 -22.9023374,-43.1815912 -22.9023186,-43.1813461 -22.9022388), 
     (-43.1793173 -22.901581,-43.1791549 -22.9015418,-43.179105 -22.9015365,-43.1790457 -22.9015482,-43.1790174 -22.9015689,-43.178994 -22.9016082), 
     (-43.1788184 -22.9020931,-43.1786726 -22.9025241,-43.1786518 -22.9025769,-43.1786063 -22.9026931), 
     (-43.1813461 -22.9022388,-43.1806028 -22.9019969,-43.1805417 -22.901977,-43.1799074 -22.9017705), 
     (-43.1799074 -22.9017705,-43.1797658 -22.9017244,-43.1793732 -22.9015989,-43.1793173 -22.901581), 
     (-43.178994 -22.9016082,-43.1788184 -22.9020931),(-43.1784337 -22.9031366,-43.1782012 -22.9036858), 
     (-43.1786063 -22.9026931,-43.17848 -22.9030174,-43.178461 -22.9030662,-43.1784337 -22.9031366))',4326); 

    routeBB := ST_Extent(geomRoute); 

    RETURN QUERY 
    SELECT pt.way, pt.name, ST_Distance(geomRoute, ST_Transform(pt.way,4326)) * 111195 as distance, 
     pt.tags, pt.operator, pt.admin_level, pt.z_order 
    FROM planet_osm_point pt 
    where routeBB && ST_Transform(pt.way,4326); 

END; $BODY$ 
    LANGUAGE plpgsql VOLATILE

來源

2017-02-15 11:16:36

如何選擇一條線附近的所有點？

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