diff --git a/lib/geokit-rails/acts_as_mappable.rb b/lib/geokit-rails/acts_as_mappable.rb
index 57a89a9..086bed8 100644
--- a/lib/geokit-rails/acts_as_mappable.rb
+++ b/lib/geokit-rails/acts_as_mappable.rb
@@ -11,7 +11,7 @@ module Glue # :nodoc:
       extend ActiveSupport::Concern
 
       module ClassMethods # :nodoc:
-        OPTION_SYMBOLS = [ :distance_column_name, :default_units, :default_formula, :lat_column_name, :lng_column_name, :qualified_lat_column_name, :qualified_lng_column_name, :skip_loading ]
+        OPTION_SYMBOLS = [ :distance_column_name, :default_units, :default_formula, :lat_column_name, :lng_column_name, :qualified_lat_column_name, :qualified_lng_column_name, :skip_loading]
 
         def acts_as_mappable(options = {})
           metaclass = (class << self; self; end)
@@ -157,6 +157,8 @@ def by_distance(options = {})
       end
 
       def with_latlng
+        qualified_lat_column_name = "CAST(#{qualified_lat_column_name} AS FLOAT)" unless qualified_lat_column_name.nil?
+        qualified_lng_column_name = "CAST(#{qualified_lng_column_name} AS FLOAT)" unless qualified_lng_column_name.nil?
         where("#{qualified_lat_column_name} IS NOT NULL AND #{qualified_lng_column_name} IS NOT NULL")
       end
 
@@ -258,6 +260,8 @@ def distance_conditions(options)
 
       def bound_conditions(bounds)
         sw,ne = bounds.sw, bounds.ne
+        qualified_lat_column_name = "CAST(#{qualified_lat_column_name} AS FLOAT)" unless qualified_lat_column_name.nil?
+        qualified_lng_column_name = "CAST(#{qualified_lng_column_name} AS FLOAT)" unless qualified_lng_column_name.nil?
         lng_sql = bounds.crosses_meridian? ? "(#{qualified_lng_column_name}<#{ne.lng} OR #{qualified_lng_column_name}>#{sw.lng})" : "#{qualified_lng_column_name}>#{sw.lng} AND #{qualified_lng_column_name}<#{ne.lng}"
         res = "#{qualified_lat_column_name}>#{sw.lat} AND #{qualified_lat_column_name}<#{ne.lat} AND #{lng_sql}"
         #Arel::Nodes::SqlLiteral.new("(#{res})") if res.present?
@@ -352,13 +356,13 @@ def flat_distance_sql(origin, units)
       end
 
       def get_lat(origin)
-        origin.respond_to?(:lat) ? origin.lat \
-                                 : origin.send(:"#{lat_column_name}")
+        origin.respond_to?(:lat) ? origin.lat.to_f \
+                                 : origin.send(:"#{lat_column_name}").to_f
       end
 
       def get_lng(origin)
-        origin.respond_to?(:lng) ? origin.lng \
-                                 : origin.send(:"#{lng_column_name}")
+        origin.respond_to?(:lng) ? origin.lng.to_f \
+                                 : origin.send(:"#{lng_column_name}").to_f
       end
 
     end # ClassMethods
diff --git a/lib/geokit-rails/adapters/postgresql.rb b/lib/geokit-rails/adapters/postgresql.rb
index 8636cf5..a09341d 100644
--- a/lib/geokit-rails/adapters/postgresql.rb
+++ b/lib/geokit-rails/adapters/postgresql.rb
@@ -3,6 +3,11 @@ module Adapters
     class PostgreSQL < Abstract
       
       def sphere_distance_sql(lat, lng, multiplier)
+        lat = "CAST(#{lat} AS FLOAT)"
+        lng = "CAST(#{lng} AS FLOAT)"
+        qualified_lat_column_name = "CAST(#{qualified_lat_column_name} AS FLOAT)" unless qualified_lat_column_name.nil?
+        qualified_lng_column_name = "CAST(#{qualified_lng_column_name} AS FLOAT)" unless qualified_lng_column_name.nil?
+
         %|
           (ACOS(least(1,COS(#{lat})*COS(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*COS(RADIANS(#{qualified_lng_column_name}))+
           COS(#{lat})*SIN(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*SIN(RADIANS(#{qualified_lng_column_name}))+
@@ -11,6 +16,10 @@ def sphere_distance_sql(lat, lng, multiplier)
       end
       
       def flat_distance_sql(origin, lat_degree_units, lng_degree_units)
+        lat_degree_units = "CAST(#{lat_degree_units} AS FLOAT)"
+        lng_degree_units = "CAST(#{lng_degree_units} AS FLOAT)"
+        qualified_lat_column_name = "CAST(#{qualified_lat_column_name} AS FLOAT)" unless qualified_lat_column_name.nil?
+        qualified_lng_column_name = "CAST(#{qualified_lng_column_name} AS FLOAT)" unless qualified_lng_column_name.nil?
         %|
           SQRT(POW(#{lat_degree_units}*(#{origin.lat}-#{qualified_lat_column_name}),2)+
           POW(#{lng_degree_units}*(#{origin.lng}-#{qualified_lng_column_name}),2))