SPATIO-TEMPORAL DYNAMICS OF SETTLEMENT SYSTEMS OF THE VOLGA AND KAMA RIVER VALLEYS
The article deals with two questions concerning the current settlement systems of the Volga and Kama valleys. The first one is devoted to spatio-temporal dynamics of population of important settlements on the banks of these rivers, which is investigated with the use of a modification of the centrographical method. The investigation has revealed some fluctuations, shifts of the Volga and Kama rivers democenter during the 20<sup>th </sup>century. This approach allows us to see a generalized development vector for the spatial systems under study. The other question concerns the length of the "step" in distances between cities and towns situated on the Volga and Kama. Among other things, discussed are options for identifying the reasons for exactly such a "step" based on the historical sources reporting the speeds of ships on the Volga river in different centuries. The approach used is associated with the spatio-temporal dynamics of linear elements of spatial systems and it enables us to trace such dynamics in relation to other rivers and roads.