How do I query objects near a point with Ruby Geocoder/Mongoid?

Question

I am trying to do something like this:

if params[:q]
  loc = Geocoder.search(params[:q])[0]
  logger.info loc.coordinates
  @places = Place.near(loc.coordinates).paginate(:per_page => 20, :page => params[:page])
else
...

It manages to geocode the query string correctly, but doesn't let me query against it. Querying a model that uses geocoder raises the following error when you try to find objects near specific coordinates:

Mongo::OperationFailure
geo values have to be numbers

The app is running Mongoid, with the Ruby Geocoder gem for geocoding.

UPDATE Here is the output of the geocode result:

    <Geocoder::Result::Google:0x102fe38c0 @data={"address_components"=>[{"long_name"=>"627", "types"=>["street_number"], "short_name"=>"627"}, {"long_name"=>"3rd Ave", "types"=>["route"], "short_name"=>"3rd Ave"}, {"long_name"=>"Manhattan", "types"=>["sublocality", "political"], "short_name"=>"Manhattan"}, {"long_name"=>"New York", "types"=>["locality", "political"], "short_name"=>"New York"}, {"long_name"=>"New York", "types"=>["administrative_area_level_2", "political"], "short_name"=>"New York"}, {"long_name"=>"New York", "types"=>["administrative_area_level_1", "political"], "short_name"=>"NY"}, {"long_name"=>"United States", "types"=>["country", "political"], "short_name"=>"US"}, {"long_name"=>"10017", "types"=>["postal_code"], "short_name"=>"10017"}], "types"=>["street_address"], "partial_match"=>true, "geometry"=>{"location"=>{"lng"=>-73.9750644, "lat"=>40.7498908}, "bounds"=>{"northeast"=>{"lng"=>-73.9750644, "lat"=>40.7498994}, "southwest"=>{"lng"=>-73.9750849, "lat"=>40.7498908}}, "location_type"=>"RANGE_INTERPOLATED", "viewport"=>{"northeast"=>{"lng"=>-73.9719270293198, "lat"=>40.7530427206802}, "southwest"=>{"lng"=>-73.9782222706802, "lat"=>40.7467474793198}}}, "formatted_address"=>"627 3rd Ave, New York, NY 10017, USA"}>
MONGODB development['places'].find({:coordinates=>{"$nearSphere"=>[-73.9750644, 40.7498908], "$maxDistance"=>0.00505209229513324}})
Completed   in 504ms

Mongo::OperationFailure (geo values have to be numbers):
  app/controllers/places_controller.rb:11:in `index'
  app/middleware/flash_session_cookie_middleware.rb:17:in `call'
  app/middleware/flash_session_cookie_middleware.rb:17:in `call'

show us loc.coordinates value. Do you use ruby 1.9.2? there is some difference between 1.9.2 and 1.8.7 output for arrays, which geocoder returns. — Mikhail Nikalyukin
@Mikhail - I updated the question with the entire result of the query — Avishai

RameshVel RameshVel · Accepted Answer · 2011-07-11T11:51:18

Your mongoid query for Geospatial query is incorrect

instead this

@places = Place.near(loc.coordinates)

You have to use this

@places = Place.near(:loc => loc.coordinates).

:loc is the column/field name got the location co-ordinates in mongo document.

Edit:

And i forgot one more thing

Google geocoder returns the co-ordinates in [lat,lng] format, but mongo requires them in [lng,lat] format. You better reverse the co-ordinate in the query.

How do I query objects near a point with Ruby Geocoder/Mongoid?

2 Answers