will disappear.The following menu is identical for discharge and rainfall records.
It produces results obtained by empirical fequency analyses, i.e. linear interpolation. The cumulative frequencies 0.2, 0.5 and 0.8 are standard, for time series longer than 10 years also the frequencies 0.1 and 0.9 could be calculated.
Notes: the mapping module is only available for annual data, and it will show the number of years with rainfall observations within the selected time period. If the user choses monthly data output, the map-button will disappear.
Alternative solution: Better results for statistical analyses of baseflows and floodflows can be obtained by the separate database tool bfff (meaning "baseflow floodflow"). It has the option to exclude months with zero-values. This is relevant for those stations, where data had been entered as "0" while instead there where no records taken.
Further more, bfff uses a different (more precise) plotting formula for the calculation of empirical frequencies.
bfff can only be applied offline, it resides in the DVS directory. It has no spatial selection and no automated graphical output. However, it permits to export daily discharges for all years in a single run.