More Mongomapper Geo problems

app.rb

mapit = Mapit.GetPostcode(params[:postcode])
EARTH_RADIUS_M = 3959

query[:latlng] = {'$nearSphere' => [mapit["lat"], mapit["lng"]], '$maxDistance' => Float(params[:within].to_i) / EARTH_RADIUS_M }

applications = Application.where(query)
@applications = applications.paginate({:order => :receiveddate.desc, :per_page=> 10, :page => params[:page]})

model.rb

class Application
  include MongoMapper::Document
  ensure_index [[:latlng, '2d']]

  key :refval, String
  key :keyval, String
  key :applicantname, String
  key :latlng, Array
  key :address, String
  key :occupier, String
  key :type, String
  key :casetype, String
  key :tradingname, String
  key :closingdate, Date
  key :recieveddate, Date
  key :details, String
  key :usetype, String
  key :status, String
  key :validfrom, Date
  timestamps!
  
  many :activities  
  many :notices  
end