Different coordinates precision when querying by model and by SQL

[pmichna]

I have a Location model, which in schema.rb looks like this:

create_table "locations", force: :cascade do |t|
  t.geometry "lonlat",     limit: {:srid=>0, :type=>"point"}
end

When I query the DB using ActiveRecord model, I get this:

Location.find(20)
Location Load (1.1ms)  SELECT  "locations".* FROM "locations" WHERE "locations"."id" = $1 LIMIT 1  [["id", 20]]
 => #<Location id: 20, lonlat: #<RGeo::Geos::CAPIPointImpl:0x3ffb552d4944 "POINT (20.983908008784056 52.23228199246873)">>

However, I need to do some more advanced query and I'm using raw SQL. I've noticed, that this way returns returns less precise values:

sql = "SELECT id, ST_X(lonlat) AS lon, ST_Y(lonlat) AS lat FROM locations WHERE id=20"
 => "SELECT id, ST_X(lonlat) AS lon, ST_Y(lonlat) AS lat FROM locations WHERE id=20"
2.2.1 :043 > ActiveRecord::Base.connection.execute(sql).first
   (1.3ms)  SELECT id, ST_X(lonlat) AS lon, ST_Y(lonlat) AS lat FROM locations WHERE id=20
 => {"id"=>"20", "lon"=>"20.9839080087841", "lat"=>"52.2322819924687"}

Why is that? What should I do to get the same precision using ActiveRecord::Base.connection.execute(sql)?

Gems' versions from Gemfile.lock:

activerecord-postgis-adapter (3.1.4)
  activerecord (~> 4.2)
  rgeo-activerecord (>= 4.0.4)

[teeparham]

The difference between these two coordinates appears to be extremely small (I got 0.0000000001 cm). Does it matter?

[pmichna]

No, it doesn't. :) You can close/delete the issue.