ArcGIS Server Service displays the Radiometric field map of the Czech Republic 1:500 000 (M. Manová, M. Matolín, 1995). This map was published by the Czech Geological Survey in the Atlas of map of Czech Republic (GEOCR500) in 1998. Data on the gamma dose rate of rocks are based on regional and detailed airborne measurement of terrestrial radiation. The data of the map illustrate the regional distribution of natural radionuclides in rocks and an above-average rock radioactivity in the Czech Republic.