Import Rain-on-Grid data

OAA Atlas 14 data are stored in 1000ths of inches, so select "in" for Units, and 1000 for Unit Scale Factor. A unit scale factor is typically used to store floating point data as integers, with the scale factor selected in order to preserve the desired level of precision.

Filename: you are required to import the frequency-precipitation ASCII file (that you can download following this tutorial).

2. Import the Gridded Data

Open the File menu and select File | Import  | Gridded Data | Importer.

You will see the Gridded Data Import Wizard open. Click on the folder icon to browse to the data directory of your HEC-HMS project.