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sqlpostgresqlpostgis

Why is PostGIS stacking all points on top of each other? (Using ST_DWithin to find all results within 1000m radius)

New to PostGIS/PostgreSQL...any help would be greatly appreciated!

I have two tables in a postgres db aliased as gas and ev. I'm trying to choose a specific gas station (gas.site_id=11949) and locate all EV/alternative fuel charging stations within a 1000m radius. When I run the following though, PostGIS returns a number of ev stations that are all stacked on top of each other in the map (see screenshot).

Anyone have any idea why this is happening? How can I get PostGIS to visualize the points within a 1000m radius of the specified gas station? 

with myplace as (
  SELECT gas.geom 
  from nj_gas gas 
  where gas.site_id = 11949 limit 1)
select myplace.*, ev.* 
from alt_fuel ev, myplace 
where ST_DWithin(ev.geom1, myplace.geom, 1000)

enter image description here

Solution

  • Resolved by using:

    WITH
  myplace as (
    SELECT geom as g
    FROM   nj_gas  
    WHERE  site_id = 11949 OR site_id = 11099 OR site_id = 11679 or site_id = 480522
  ), myresults AS (
SELECT ev.* 
FROM   alt_fuel AS ev
JOIN   myplace AS mp
  ON   ST_DWithin(ev.geom, mp.g, 0.1))
select * from myresults```

Thanks so much for your help @ThingumaBob and @JimJones ! Greatly appreciate it.