Geokit and rails 3

Question

I am using the geokit gem and plugin with rails 3. It seems there is a known issue with them, which can be seen here http://github.com/andre/geokit-rails/issues#issue/15

Now, I tried to follow the solution provided at the bottom. I pasted that function definition, at the end of the file, just above acts_as_mapable, and just after the first time it was called, but nothing happened each time.

Any idea what else can be done?

Thanks

Answer 1

I ran into similar problems upgrading my app to rails 3. I'm still using Geokit for geocoding but Active Record scopes for distance based database queries. It's pretty convenient, and you still get all of the Active Record 3 goodness. Here's an example from my User model:

scope :near, lambda{ |*args|
                  origin = *args.first[:origin]
                  if (origin).is_a?(Array)
                    origin_lat, origin_lng = origin
                  else
                    origin_lat, origin_lng = origin.lat, origin.lng
                  end
                  origin_lat, origin_lng = deg2rad(origin_lat), deg2rad(origin_lng)
                  within = *args.first[:within]
                  { 
                    :conditions => %(
                      (ACOS(COS(#{origin_lat})*COS(#{origin_lng})*COS(RADIANS(users.lat))*COS(RADIANS(users.lng))+
                      COS(#{origin_lat})*SIN(#{origin_lng})*COS(RADIANS(users.lat))*SIN(RADIANS(users.lng))+
                      SIN(#{origin_lat})*SIN(RADIANS(users.lat)))*3963) <= #{within}
                    ),
                    :select => %( users.*,
                      (ACOS(COS(#{origin_lat})*COS(#{origin_lng})*COS(RADIANS(users.lat))*COS(RADIANS(users.lng))+
                      COS(#{origin_lat})*SIN(#{origin_lng})*COS(RADIANS(users.lat))*SIN(RADIANS(users.lng))+
                      SIN(#{origin_lat})*SIN(RADIANS(users.lat)))*3963) AS distance
                    )
                  }
                }

Here's a blog post with a little more detail on the subject: http://stcorbett.com/code/distance-queries-with-rails-3-without-geokit/

Answer 2

jlecour's port to rails 3 should solve any issues you were having last year.

Make sure you're using mysql or postgres if you're doing distance calculations.