FlamMap Lesson 4

Minimum Travel Time

The minimum travel time (MTT) feature is a two-dimensional fire growth model. It calculates fire growth and behavior by searching for the set of pathways with minimum fire spread times from point, line, or polygon ignitions. MTT has a wide variety of uses, in this lesson you will learn how to use MTT to simulate a fire from a point source ignition using variable dead fuel moisture conditions. A separate lesson using the MTT Burn Probabilities feature is also available, it is not necessary to complete this lesson before doing the Burn Probability Lesson.

The data files for this tutorial are found in your ...FlamMap6\Tutorial folder (directory).

Open your Project

If you have closed your project or shut down FlamMap, you can reopen the project by selecting the File > Open command from the menu bar. In the "Open" dialog box select the project file FirstTutorial.fmp and click the Open button. Your FlamMap project will display just the way it was when you last saved it.

Create a MTT Simulation

Since much of the input for this new run is the same as the "Variable Fuel Moistures" run we can copy "Variable Fuel Moistures" and add the additional information needed for a MTT fire simulation.

Copy by right-clicking the Variable Fuel Moistures line in the "Tree" pane and select Copy... from the shortcut menu.

Inputs Tab

A copy of the "Run:" dialog will open and make the following changes.

• Change the name of the copied run to "MTT Point Ignition".
• In the Winds area select the Wind Direction radio button. This will provide a constant wind direction and wind speed for this fire simulation,
• and change the Wind Speed to 12 mph.
• Leave all other inputs as they were in the "Variable Fuel Moistures" run.

Fire Behavior Options Tab

An MTT simulation can also generate any of the outputs listed on the Fire Behavior Options tab. Feel free to select any additional outputs from this tab. Select at least the Fireline Intensity and Rate of Spread outputs. Make sure to click the Apply button after making changes on this tab.

Minimum Travel Time Tab

On the Minimum Travel Time tab make the following inputs.

• In the Ignitions area select the From File radio button, click and select the Open Ignitions File ... option. Navigate to your ...FlamMap6\Tutorial folder and open "PointIgnition.shp". This is a shapefile with a single point we will use for the ignition.
• In the Inputs area,
  • change Resolution of Calculations to 60 meters,
  • change Maximum Simulation Time to 600 minutes to simulate a two day fire with a five hour per day burning period,
  • leave Interval for Minimum Travel Path at 500 meters,
  • change Spot Probability to 0.10,
  • leave Spotting Delay at 0,
  • leave Lateral Search Depth at 6,
  • and leave Vertical Search Depth at 4.
• Leave the Barriers area empty.
• In the Outputs area select all the available outputs.

Click the Apply button and the Minimum Travel Time tab should look like this.

The status bar should indicate Inputs OK, the number of outputs selected on both the Fire Behavior Options and Minimum Travel Time tabs, and existing output status.

It is important to emphasize one of the major MTT assumptions at this point; all wind and fuel moisture conditions are constant throughout the simulation period. Burning conditions can vary across the landscape when utilizing conditioning and/or gridded winds, but will not vary during the 600 minutes of this simulation.

Launch

Not it's time to see some results, click the Launch button and the "FlamMap Progress..." dialog box appears.

When the run is completed, click OK to return to the "Run:" dialog box. Then click OK  in the "Run:" dialog box to return to the "Project" window where you can view the outputs of the run.

Outputs

After closing the "Run:" dialog box the "Project" window will look like this.

Zoom into the area of the simulation with the Zoom In button. Then expand the MTT Point Ignition run item (by clicking the icon) in the "Tree" pane to show all the output items.

Save Your Project

You should save this project by following the procedures from the first lesson. Keep the project name "FirstTutorial.fmp".

You're Finished

Now open the Evaluating MTT Outputs lesson to further explore the results of this run.