2

I have the following query on a PostGIS Database

SELECT row_to_json(fc) 
FROM ( 
  SELECT 'FeatureCollection' As type, 
         array_to_json(array_agg(f)) As features 
  FROM (
    SELECT 'Feature' As type, 
      ST_AsGeoJSON(lg.geom)::json As geometry, 
      row_to_json((id, name)) As properties 
    FROM lines As lg) As f
  ) As fc;

which returns a GEOJSON Object of all features in the database.

How do i filter the results by a Bounding Box already in the query?

1 Answer 1

4

You can use the && operator on a new box. Don't forget to use the same SRID for the box and for your data.

SELECT row_to_json(fc) 
 FROM ( 
     SELECT 'FeatureCollection' As type, 
            array_to_json(array_agg(f)) As features 
       FROM (
         SELECT 'Feature' As type, 
         ST_AsGeoJSON(lg.geom)::json As geometry, 
         row_to_json((id, name)) As properties 
      FROM lines As lg
      WHERE lg.geom && 
          ST_SETSRID(
            ST_MakeBox2D(
                ST_MakePoint(p_BB_XLong_MIN_3857, p_BB_YLat_MIN_3857),
                ST_MakePoint(p_BB_XLong_MAX_3857, p_BB_YLat_MAX_3857)),
          3857)
) As f) As fc;
2
  • looks great. However i am trying to fix this Error, not having much luck: "subquery in FROM must have an alias"
    – niaR
    Feb 23, 2019 at 7:57
  • ah ok, an extra closing ). It's now removed
    – JGH
    Feb 23, 2019 at 13:19

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