# File lib/geo_ruby/simple_features/geometry.rb, line 84
      def as_ewkt(allow_srid=true,allow_z=true,allow_m=true)
        if allow_srid
          ewkt="SRID=#{@srid};"
        else
          ewkt=""
        end
        ewkt << text_geometry_type 
        ewkt << "M" if @with_m and allow_m and (!@with_z or !allow_z) #to distinguish the M from the Z when there is actually no Z... 

        ewkt << "(" << text_representation(allow_z,allow_m) << ")"        
      end