embrs.utilities.fire_util#

Various sets of constants and helper functions useful throughout the codebase

class embrs.utilities.fire_util.UtilFuncs#

Various utility functions that are useful across numerous files.

get_cell_polygons() → list#

Converts a list of cell objects into the minimum number of shapely.Polygon required to describe all of them

Parameters:

cells (list) – list of Cell objects to be converted

Returns:

list of shapely.Polygon representing the cells

Return type:

list

get_dominant_fuel_type() → int#

Finds the most commonly occurring fuel type within a fuel map.

Parameters:

fuel_map (np.ndarray) – Fuel map for a region

Returns:

Integer representation of the dominant fuel type. See fuel_names

Return type:

int

get_indices_from_xy(y_m: float, cell_size: float, grid_width: int, grid_height: int) → Tuple[int, int]#

Get the row and column indices in a backing array of a cell containing the point (x_m, y_m).

Does not require a FireSim object, uses ‘cell_size’ and the size of the array to calculate indices.

Parameters:

  • x_m (float) – x position in meters where indices should be found

  • y_m (float) – y position in meters where indices should be found

  • cell_size (float) – cell size in meters, measured as the distance across two parallel sides of a regular hexagon

  • grid_width (int) – number of columns in the backing array of interest

  • grid_height (int) – number of rows in the backing array of interest

Raises:

ValueError – if x or y inputs are out of bounds for the array constructed by ‘cell_size’, ‘grid_width’, and ‘grid_height’

Returns:

tuple containing [row, col] indices at the point (x_m, y_m)

Return type:

Tuple[int, int]

get_time_str(show_sec=False) → str#

Returns a formatted time string in m-h-s format from the time in seconds.

Useful for generating readable display of the time.

Parameters:

  • time_s (int) – time value in seconds

  • show_sec (bool, optional) – set to True if seconds should be displayed, False if not, defaults to False

Returns:

formatted time string in h-m-s format

Return type:

str

static hexagon_vertices(x: float, y: float, s: float) → list#

Calculates the locations of each of a hexagons vertices with center (x,y) and side length s.

Parameters:

  • x (float) – x location of hexagon center

  • y (float) – y location of hexagon center

  • s (float) – length of hexagon sides

Returns:

list of (x,y) points representing the hexagon’s vertices

Return type:

list

class embrs.utilities.fire_util.CellStates#

Enumeration of the possible cell states.

Attributes:

  • BURNT (int): Represents a cell that has been burnt and has no fuel remaining.

  • FUEL (int): Represents a cell that still contains fuel and is not on fire.

  • FIRE (int): Represents a cell that is currently on fire.

class embrs.utilities.fire_util.FireTypes#

Enumeration of the possible fire types.

Attributes:

  • WILD (int): Represents a fire that occurred naturally.

  • PRESCRIBED (int): Represents a fire that was started in a controlled manner, burns with lower intensity.

class embrs.utilities.fire_util.FuelConstants#

Various values and dictionaries pertaining to modelling of fuel types.

Attributes:

  • burnout_thresh (float): fuel content which dictates what is considered to be a burned out cell.

  • ch_h_to_m_min (float): float that converts chains/hr to m/min.

  • fbfm_13_keys (list): list of ints corresponding to each of Anderson’s 13 FBFMs.

  • fuel_names (dict): dictionary where keys are ints for each FBFM and values are the names of each fuel type.

  • fuel_type_revers_lookup (dict): dictionary where keys are the fuel type names and values are the ints for each FBFM.

  • init_fuel_table (dict): dictionary of the initial fuel content of each fuel type.

  • nom_spread_prob_table (dict): dictionary of dictionaries for each fuel type’s nominal spread probabilities.

  • nom_spread_vel_table (dict): dictionary of nominal spread velocities for wildfires for each fuel type.

  • dead_fuel_moisture_ext_table (dict): dictionary of each fuel type’s dead fuel moisture of extinction.

  • fuel_consumption_factor_table (dict): dictionary of each fuel type’s mass-loss curve weighting factor.

  • fuel_color_mapping (dict): dictionary mapping each fuel type to the display color for visualizations.

class embrs.utilities.fire_util.RoadConstants#

Information on the modelling of different road types.

Attributes:

  • major_road_types (list): list of the names of each of the major road types defined by OpenStreetMap.

  • road_fuel_vals (dict): dictionary mapping road types to the amount of fuel modelled along them.

  • road_color_mapping (dict): dictionary mapping road types to their display color for visualizations.

class embrs.utilities.fire_util.HexGridMath#

Data structures to help with handling cell neighbors in a hexagonal grid.

Attributes:

  • hex_angle (float): float representing the angle between neighboring hexagon cell centers.

  • even_neighborhood_mapping (dict): dictionary that maps relative indices of a cell’s neighbors to unit vectors between them, for even rows.

  • odd_neighborhood mapping (dict): dictionary that maps relative indices of a cell’s neighbors to unit vectors between them, for odd rows.

  • even_neighborhood (list): list of relative indices of a cell’s neighbors, for even rows.

  • odd_neighborhood (list): list of relative indices of a cell’s neighbors, for odd rows.

class embrs.utilities.fire_util.ControlledBurnParams#

Parameters differentiating PRESCRIBED fires from WILD

Attributes:

  • nominal_prob_adj (float): factor adjusting the nominal spread probability.

  • nominal_vel_adj (float): factor adjusting the nominal spread velocity.

  • consumption_factor_adj (float): factor adjusting the fuel consumption factor W.

  • min_burnable_fuel_content (float): minimum fuel fraction remaining in a neighboring cell for a possible ignition

  • burnout_fuel_frac (float): fraction of fuel at ignition remaining in burning cell at which it stops burning.

class embrs.utilities.fire_util.WindAdjustments#

Mapping of wind speed to Lorentzian curve parameters, used to calculate alpha_w

Attributes:

  • wind_speed_param_mapping (dict): dictionary mapping wind speeds (km/h) to Lorentzian parameters (A, gamma, C)

Classes

CellStates()

Enumeration of the possible cell states.

ControlledBurnParams()

Parameters differentiating PRESCRIBED fires from WILD

FireTypes()

Enumeration of the possible fire types.

FuelConstants()

Various values and dictionaries pertaining to modelling of fuel types.

HexGridMath()

Data structures to help with handling cell neighbors in a hexagonal grid.

RoadConstants()

Information on the modelling of different road types.

UtilFuncs()

Various utility functions that are useful across numerous files.

WindAdjustments()

Mapping of wind speed to Lorentzian curve parameters, used to calculate alpha_w