Dialectology, the study of language in its social and geographical ramifications, has profited this way for the same number of years by its firm tradition of the use of dialect maps. (Credits for the oldest dialect map go to the German scholar J.A. Schmeller for his Bavarian dialect map of 1821.) Insights into scale and direction of spreading and grouping, into its manner and causes, come up far more easily by the help of a graphical display than through tables and digits. The eye is an excellent pattern recognizer. A map is an indispensable tool for guiding thoughts.

Statistical reworking of data adds essential insights which are not always deductable from a map. A map should always be a starting point, not a terminal node.

By combining maps relations between phenomena show up: one theme may systematically combine with another. Such combinations draw attention to structural interconnections which may require more in-depth research.

Situations continuously change: relations may show a substantially different picture in the past. It is always important to compare modern data with data from past periods of time (when possible).