Abstract
The crowd-sourcing approach should be implemented into a new historical geoportal of Poland due to its increasing potential in WebGIS. Registered users will be able to acquire spatial data from various map series. As it requires feature class harmonization, a common symbol classification should be proposed. It will be based on chosen topographic maps of Polish land from the 19th and 20th centuries. Feature classes derived from archival maps will be standardized and reclassified, but with no information lost. This will be done in four steps which require: data acquisition, map content harmonization, feature class typification and attribute table elaboration. In addition, four methods of data harmonization can be distinguished: symbol sequence, semantic analogies, spatial relations and a combined method. The paper covers the elaboration of two thematic layers - roads and railways based on three topographic maps (Austrian 1:75 000, German 1:100 000, Russian 1: 126 000).