For Markov graphic source, it is well known that the conditional runlength coding for the runs of correct prediction is optimum for data compression. However, because of the simplicity in counting and the stronger concentration in distrubution, the incremental run is possibly a better parameter for coding than the run itself for some cases. It is shown that the incremental-runlength is also geometrically distributed as the runlength itself. The distribution is explicitly described with the basic parameters defined for a Markov model.