A physical DFD describes the actual way in which system operates, including personnel, physical locations and media used in transfer of information. A logical DFD attempts to reduce this to the actual data flows and the processes transforming the data without regard to the physical manner by which this is achieved.
DFD halisi inaeleza jinsi mfumo unavyofanya kazi, ikijumuisha wafanyakazi, maeneo halisi na midia inayotumika kuhamisha taarifa. DFD yenye mantiki inajaribu kupunguza hii hadi mtiririko halisi wa data na michakato ya kubadilisha data bila kuzingatia jinsi ya kawaida ambayo hii inafikiwa.