Same custom method validation with different fields of same type

How can I refactor this coordinate validation routine so that I can use
this method with other fields of the same type, for instance, with
"full_last_position" and also maintain the cleanliness of the code and
avoiding repeating method code?

class Provider < ActiveRecord::Base
  include UtilsModule
  attr_accessor :full_target_area_coordinate, :full_last_position # this
field validates and saves coordinate

  validate :full_target_area_coordinate, :is_valid_coordinate?

  def is_valid_coordinate? # searches local geo_codes table for valid
zip
    coord = self.full_target_area_coordinate.to_str
    match = coord.match(/^(-?\d{1,2}\.\d{6}),\s*(-?\d{1,2}\.\d{6})$/)
    if match.nil? # invalid format
      errors.add(:target_area_coordinate, :invalid)
      return false
    end

    self.target_area_coordinate =
UtilsModule.convert_coordinate(self.full_target_area_coordinate)
    return true
  end

end

  def is_valid_coordinate? # searches local geo_codes table for valid
zip
    coord = self.full_target_area_coordinate.to_str

    coord = self.to_str

    match = coord.match(/^(-?\d{1,2}\.\d{6}),\s*(-?\d{1,2}\.\d{6})$/)
    if match.nil? # invalid format
      errors.add(:target_area_coordinate, :invalid)

errors.add(self.to_sym, :invalid)

      return false
    end

    self.target_area_coordinate =
UtilsModule.convert_coordinate(self.full_target_area_coordinate)

just return true here.
i would suggest separating the conversion from the validation.

kind regards,
--botp

How can I refactor this coordinate validation routine so that I can use
this method with other fields of the same type, for instance, with
"full_last_position" and also maintain the cleanliness of the code and
avoiding repeating method code?

Maybe what you're looking for is ActiveModel::Validator ?