Show posts nearby with Rails Model

post.rb

  def self.close_by(lat1, lon1)
    posts_around = []
    Post.where("latitude IS NOT NULL AND longitude IS NOT NULL").order('id DESC').each do |post|
      distance = Post.new.distance(lat1.to_f, lon1.to_f, post.latitude.to_f, post.longitude.to_f)
      radius = Setting.find(1).usersight
      if (distance <= radius.to_f)
        post_array = {}
        if post.user.nil?
          username = ""
        else
          username = post.user.username
        end
        post_array.merge!(:latitude   => post.latitude,
                          :longitude  => post.longitude,
                          :id         => post.id,
                          :body       => post.body,
                          :username   => username,
                          :user_id    => post.user_id,
                          :created_at => post.created_at,
                          :address    => post.address)
        posts_around.push(post_array)
      end
    end
   posts_around
  end