A polygon that represents the maximum inundated area for the largest flood scenario is necessary to trim other required data down to a manageable size. The inundated area polygon for the maximum flood inundation scenario is typically generated by the hydraulic engineer while performing inundation mapping in HEC-GeoRAS (bounding polygons). These bounding polygons are stored in the HEC-GeoRAS geodatabase for a given study. This maximum inundated area needs to be converted to a shapefile for later use.

To convert the maximum inundated area bounding polygon to a shapefile:

  1. Start ArcCatalog. The ArcCatalog window opens.
  2. From the first pane (the Catalog Tree), browse to the folder that contains the geodatabase file for the study.

  3. Once the geodatabase file appears in the Contents tab of the main window, double-click on the geodatabase filename (i.e., Truman_SDF.mdb). Next, double-click on the geodatabase feature dataset (i.e., RasResults).

    Figure: Contents Tab - Geodatabase File

  4. The bounding polygon file created by HEC-GeoRAS should appear in the list (i.e., bP001). Right-click on the bounding polygon filename. From the shortcut menu, point to Export and select To Shapefile (single).

    Figure: Export Shortcut Menu

  5. The Feature Class to Feature Class dialog box opens.

  6. The Input Features box should contain the name of the selected bounding polygon file. Choose the location to store the shapefile by clicking next to the Output Location dialog box. The Output Location browser opens. Browse to the folder to store the shapefile, click Add. The Output Location browser closes, and the pathname with the selected folder appears in the Output Location box of the Feature Class to Feature Class dialog box.

    Figure: Feature Class to Feature Class Dialog Box


    Figure: Output Location Browser

  7. In the Output Feature Class box, provide a name for the shapefile (i.e., Truman_ExtremeFail_BoundingPolygon).

  8. Click OK. The Feature Class to Feature Class dialog box closes, and the Feature Class to Feature Class Compute dialog box opens. This dialog box contains information on if the creation of the float file was successful and how long it took to create the binary file. Click Close. The Feature Class to Feature Class Compute dialog box closes and the shapefile appears in the location selected.

    Figure: Feature Class to Feature Class Compute Dialog Box