Inundation Analyst

Inundation Analyst is a Vflo™ extension that provides images, animations, and data showing the extent of forecast or simulated inundation, which is an indication of flood risk. The extension’s inundation products are especially useful for flood management applications: forecast inundation is useful for operational decisions, warning and notification, and coordinating emergency response.

Inundation Analyst operates independently from the Vflo™ model, but can use data exported from Vflo™ as input for generating inundation forecasts. Inundation Analyst requires a digital elevation model (DEM), a flow direction map, a channel flow direction map, and stage data. If flow direction maps are in a different resolution than stage data, they will be filtered automatically. All data inputs must be in ESRI ASCII grid or binary grid format.

An Inundation Analyst license must be present in the Inundation Analyst directory in order to run Inundation Analyst. To order Inundation Analyst, contact Vieux & Associates, Inc. Please note that adaptation or modification of Inundation Analyst for use in real-time applications is not allowed in the desktop license.

Data requirements

All input data must be in ESRI ASCII or binary grid format, as with AutoBOP. Flow direction is extracted from thr DEM. The DEM must be in units of either feet or meters.  Stage data inputs may be those exported from a Vflo™ model (see Exporting stage data for instructions). It is not necessary for the grid definition of the flow direction map to be the same as that of the stage files. For example, a LiDAR DEM at 5-meter resolution could be used to prepare a flow direction grid for use in Inundation Analyst, so long as coordinate system/projection information exists to map this grid onto the exported stage grid from Vflo™. Background images can be included at any resolution, so long as their extent is the same as that of the DEM and flow direction map. Background images must be in JPEG or bitmap format.

Creating an Inundation Analyst model

High-resolution flow direction maps for use in Inundation Analyst are created from DEM files using the AutoBOP process. This is available from the File | New menu. See AutoBOP for detailed steps for creating a model; the final steps of specifying cell parameters do not apply.

Once created, Inundation Analyst model files can be saved to disk with the extension .indx, and reloaded later, using the File | Save and File | Load menus respectively.

Loading data to Inundation Analyst

To generate inundation results from stage data, select the Solve | Generate Inundation from Stage menu. A data loading dialog will appear. Click the Add button, then navigate to the ASCII stage files exported from Vflo™. Multiple files can be selected at once by holding down the SHIFT button while highlighting multiple files. Select the appropriate units at the bottom of the window: Feet or Meters.

Stage files should be listed in the order that the animation should proceed. Files exported from Vflo™ bear a timestamp in the filename that may be useful for ordering stage files chronologically. If the files are not in appropriate order, select a file and use the Move Up and Move Down buttons to move the file up or down the list.

Once all stage files are listed in the appropriate order, click OK. A Progress window will appear, indicating that data is being loaded. Once all of the images have been produced, the Progress window will disappear and the first image will be shown in the primary Inundation Analyst window.

Controlling animations

The Animation menu contains the tools necessary to generate and control animation sequences.

To show the images in an animation sequence, select Animation│Play. This will cause the images to animate on the screen. To stop the animation, select Animation | Pause. To control the speed of the animation sequence, select Animation | Speed. Then choose the desired speed from the drop down menu.

Exporting data

To export inundation data, select Export | Export ASCII. The grids that are inundated are identified according to the column and row in the output ASCII grids. The animation itself may also be exporte as images using the Export | Export Images menu.