app/serializers/map_serializer.rb
class MapSerializer < ActiveModel::Serializer
include BaseSerializer
attributes :id, :name, :description, :additional_info, :contacts, :tags,
:created_at, :updated_at
has_many :geo_data
def geojson_feature_hash
feature = ::GeoJSON::build_feature nil, object.id, object.geojson_properties
encoded = ::GeoJSON::encode_feature(feature)
encoded["properties"]["geo_data"] = object.location
encoded
end
end