Between retrogression and progression – a proposal for a new method to recreate the historical building layout of settlement units

The use of cartographic sources and methods are the basic tools of historical geography. One of the main research trends in this field is the analysis of the spatial layout and number of old settlement units. The confrontation of maps with historical data allows the drawing of a town’s area at a certain time to be studied. The retrogression (R) and progression (P) methods that are currently used are imperfect and the model created (map) is usually incomplete and its reliability is limited. In the author’s opinion, the joining of retrogression and progression (a new method; combined – K) 1 increases the quality of cartographic reconstruction of natural and cultural landscapes. The use of basic mathematical methods from the scope of set operations means the component reliability of the researched cartographic model can be varied because the common part of the retrogression and progression cartographic model represents mutual verification of source data. Quantitative effectiveness assessments of retrogression (R), progression (P) and the combined method (K) can be made for countable elements (e.g. buildings). As part of the conducted study, the effectiveness of separate methods was calculated: R = 76% for retrogression, P = 59% for progression and K = R ∪ P = 85% for the combined method. The mutual verification of the methods (R ∩ P) included 45% of residential buildings. The author describes the proposition of a new method and the course of verification research.