The precipitation-radar images show only qualitative information on precipitation.The radar images are based on non-processed raw data. Their quality is limited to non-quantitative information, since radar is only an indirect method of measuring precipitation, based on reflectivity. Quantitative information from radar measurements is obtained by comparing the data with conventional precipitation measurements. However, real-time measurements aren't possible yet. This so-called quasi-calibrated data is neither produced regularly nor updated. For different technical reasons radar information is still incomplete and patchy. The spatial resolution of the precipitation radar image is 4 km x 4 km and the temporal resolution is 15 minutes. Based on the magnitude of radar reflection seven different intensities of precipitation were distinguished.