Alteration of the ethnic diversity and ethnic segregation index in Latvia during the first and second independence periods

It is a well-known fact that the Baltic area is traditionally one of the most diverse regions of Europe in terms of ethnic concerns; we can observe in many settlements that four or even five religions have their own churches, cemeteries and at least as many ethnic groups are having their schools etc. Regarding geography literature, no generally accepted method has been applied yet to measure the population’s diversity and spatial segregation; in most cases only the number and ratio of ethnic groups were described. This research paper proposes a different approach: the adaptation of the so-called Simpson’s Diversity Index, based on probability theory and originally used by ecologists to measure biodiversity, to human geography. The study seeks the answers to: where, when, why and how has the Ethnic Diversity and Ethnic Segregation Index changed in Latvia during the first and second independence periods? What kind of spatial patterns are possible to observe on the basis of the transformation? The enormous data is processed by modern GIS software products and projected on thematic maps.