This appendix is written to explain steps for converting data to input types that are supported by HEC-FIA; it is for users who have not upgraded to the latest version of HEC-RAS 5.0. To see the steps for getting the correct data for input to HEC-FIA from HEC-RAS 5.0, go to Appendix G.
The geographic information system (GIS) pre-processing that is required for an HEC-FIA study can be handled through the use of the ESRI ArcGIS® Desktop software. Information and availability about the ArcGIS® Desktop software is available from ESRI (www.esri.com). The software should include ArcMap®, the ArcGIS® 3D Analyst extension, and the ArcGIS® Spatial Analyst extension. Optionally, users can use other GIS platforms like GRASS (http://grass.osgeo.org/) or QGIS (http://www.qgis.org/en/site/)
There are several GIS pre-processing steps that need to be completed before creating a study in HEC-FIA. Depending on the level of detail in the study, not all of the following need to be utilized:
- Preparation of maximum inundation depth grids
- Preparation of duration and arrival time grids
- Creation of maximum inundation area polygon
- Generation of the hazard area boundary
- Preparation of a digital terrain model
- Preparation of arrival time grid for depths two feet and greater
- Preparation of various items developed by HEC-GeoRAS (Hydrologic Engineering Center's ArcGIS extension for processing geospatial data for HEC-RAS)
- Preparation of emergency planning zone (formerly defined as impact area in HEC-FIA Version 3.0) polygons
- Preparation of double warning time polygon
- Agricultural grid preparation
Each of these steps is explained in the following sections.