Quick start This document outlines the user interface of the computer program discussed in the following paper: Trunfio G.A., D'Ambrosio D., Rongo R., Spataro W., Di Gregorio, S., "A New Algorithm for Simulating Wildfire Spread Through Cellular Automata" ACM Transactions on Modeling and Computer Simulation, 22(1) For further information please refer to the paper or contact the authors.

Opening an existing landscape file Use the button to load a landscape file from disk. Once a landscape has been loaded, it is automatically shown in a map window (see the Figure below). It is always possible to open a new (different map windows may show different portions of the map window using the button landscape).

Parameters and variables

Map window

Cell inspector

Status bar Other relevant components of the user interface are: - the “Cell inspector”, which allows to view and/or modify the cells’ properties;

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the “Parameters and variables” grid, which allows to view and/or modify the simulation parameters and to monitor some informative variables; the status bar, which indicates the current step of the simulation and the elapsed time. It also contains two state buttons described later, namely “Track ellipses” and “Standard CA”.

Using the button the current state of the landscape can be saved to disk in a proprietary binary format. Be careful not to overwrite the initial state of the landscape (there is currently no automatic backup function). To export raster files in ESRI ASCII format use the button .

Editing cells The cell inspector, which can be activated using the button , allows to view/modify the cell’s properties. For example, to define an ignition point in the landscape: , select the target cell by clicking on it in the map window; if necessary 1. using the tool use the Zoom and Pan tools available in the toolbar. When selected, the cell will be highlighted (see the Figure below). Note that it is possible to select more than one cell holding down the control key. Also, the tool of cells;

can be used to select rectangular regions

Selected

2. open the cell inspector using the button ; 3. set the value of the property “state” to 1; note that ignited cells are coloured in red in the map window.

The property “state” can take the values listed below (the corresponding cell colours showed in the map window are specified in brackets): -

NOT_COMBUSTIBLE = -1 (black) NOT_IGNITED=0 (depending on the fuel model) BURNING=1 (red) BURNED=2 (gray)

Clearly, every property of the cells can be assigned as described above. For example, to assign a fuel type to the selected cells simply set the value of the property “fuelType” (the latter can take the integer values corresponding to the standard fuel types of BEHAVE).

Creating a new landscape The button opens a form which allows for defining all the relevant characteristics of a new landscape. First, the name of the binary landscape file has to be entered in the proper text box.

File name

Then, the structure of the raster landscape has to be defined. It is possible to either select a georeferenced Digital Elevation Model (DEM, in ESRI ASCII format) or to generate a rectangular landscape providing its origin, the cell size, a constant slope and a constant terrain aspect. For example, in the Figure below a DEM has been selected and its preview is shown:

The next step consists of assigning a fuel type to each cell of the landscape. As shown below, the user can import a suitable georeferenced raster in ESRI ASCII format, in which a fuel code is associated to each cell. Fuel codes must be defined according to the standard fuel models of BEHAVE. As an alternative, the user interface allows to assign the same fuel code to all cells (i.e., for defining a constant-fuel landscape).

Then, to each cell the couple of values should be assigned. As shown in the Figure below, the user interface allows to import gridded wind fields in ESRI ASCII format. Wind fields can be computed, given an average constant wind vector, through programs like WindNinjia (a computer program that computes spatially varying wind fields for wildland fire applications - http://www.firelab.org). Although it is always recommended the use of accurate spatially-varying wind fields, it is also possible to set a constant wind for the entire domain as done in the form represented below.

Currently the wind direction is specified in degrees according to the goniometric convention (i.e. counterclockwise starting from the east). Also, the wind direction is the direction that the wind is coming from (e.g., a 270° direction correspond to a wind blowing from south to north). Another important information that should be provided at the cell level, is the fuel moisture content. Similarly to the other data, the user interface allows to import a gridded moisture value for each fuel category. Alternatively, a uniform moisture can be assigned as done in the Figure below.

Once the relevant data have been entered, the “Create” button starts the process of building the landscape. This involves: 1. creating the internal raster of cells according to the provided input (DEM or constant-slope raster); 2. pre-computing the maximum slope and the aspect for each cell; 3. assigning the proper fuel code, wind speed, wind direction and fuel moistures to each cell.

At the end of the process a new map window opens and the new file is automatically saved to disk.

Running a simulation To run a simulation: 1. 2. 3. 4. 5.

open or create a landscape; if necessary set the ignition points; using the button open the “Parameters and Variables” form; set the desired values of the end time (in min) optionally, set the neighbourhood radius and the time step multiplier (allowed: between 0.1 and 1; suggested: between 0.7 and 1.0);

parameters variables

6. use the button to begin the simulation; if a map window is already open, it will be updated at each step (this of course will slow down the simulation). The simulation will end when currentTime=endTime. At the end of the simulation use the to reset the status of the landscape that had been loaded from disk. button During the simulation: - it is always possible to stop the simulation using the button . - use the button to pause the computation, for example to export the current state of the CA (see below for the raster exporting function). The button can be used to carry out a single simulation step. This is especially useful when used in the “tracking ellipses” mode (see below). Note that the button can be used for exporting in ESCRI ASCII format a raster based on any of the cell’s properties. The current values of the cells’ properties are used to build the raster (i.e. the raster will reflect the current configuration of the landscape).

Tracking the ellipses By clicking the “Track ellipses” state button on the status bar (at the bottom of the main window), it is possible to track the ellipses that are generated inside each burning cell (see the paper above). Note that this will slow-down dramatically the simulation. To ensure that the simulation is suspended after each step use the button . This operating mode can be disabled by clicking again on the same state button.

Activating the standard CA By clicking the “Standard CA” state button on the status bar (at the bottom of the main window), the simulation will be carried out using a standard CA (i.e., a point-to-point ignition CA, see the paper) instead of the enhanced CA proposed in the paper. This operating mode can be disabled by clicking again on the same button.