What input data does the IDF Curve Tool need?
In short: The IDF Curve Tool accepts either raw rainfall time-series data or a precomputed rainfall-intensity table. Raw data is the usual choice because the tool can aggregate the record, calculate maximums for each duration, and build the intensity table automatically.
Option 1: raw rainfall data
Prepare an Excel workbook with a valid Excel date/time column and rainfall observations in chronological order. In the Input Raw Data tab, select the worksheet and set the actual sampling interval, such as 5, 10, 15, or 30 minutes, or hourly. This setting must match the data; an incorrect interval changes the aggregation durations and produces incorrect intensities.
A long, quality-controlled record is preferable. Review units, duplicate timestamps, gaps, and the completeness of the first and last analysis years before fitting a distribution. The software can identify gaps and offers gap-filling choices, but any filled or excluded data should be documented.
Option 2: a precomputed intensity table
If maximum rainfall intensities have already been calculated for every duration and year, load that table through the Input Data tab. This bypasses the raw-data aggregation step. Ensure durations, years, and intensity units are clearly defined and internally consistent.
Follow the import steps in the IDF Curve Tool tutorial, and review the calculation sequence in the formula reference.