NAME
r.ros - Generates rate of spread raster maps.
Generates three, or four raster map layers showing the base (perpendicular) rate of spread (ROS), the maximum (forward) ROS, the direction of the maximum ROS, and optionally the maximum potential spotting distance for fire spread simulation.
KEYWORDS
raster,
fire,
spread,
rate of spread,
hazard,
model
SYNOPSIS
r.ros
r.ros --help
r.ros model=name [moisture_1h=name] [moisture_10h=name] [moisture_100h=name] moisture_live=name [velocity=name] [direction=name] [slope=name] [aspect=name] [elevation=name] base_ros=name max_ros=name direction_ros=name [spotting_distance=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
- --overwrite
- Allow output files to overwrite existing files
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- model=name [required]
- Raster map containing fuel models
- Name of an existing raster map layer in the user's current mapset search path containing the standard fuel models defined by the USDA Forest Service. Valid values are 1-13; other numbers are recognized as barriers by r.ros.
- moisture_1h=name
- Raster map containing the 1-hour fuel moisture (%)
- Name of an existing raster map layer in the user's current mapset search path containing the 1-hour (<.25") fuel moisture (percentage content multiplied by 100).
- moisture_10h=name
- Raster map containing the 10-hour fuel moisture (%)
- Name of an existing raster map layer in the user's current mapset search path containing the 10-hour (.25-1") fuel moisture (percentage content multiplied by 100).
- moisture_100h=name
- Raster map containing the 100-hour fuel moisture (%)
- Name of an existing raster map layer in the user's current mapset search path containing the 100-hour (1-3") fuel moisture (percentage content multiplied by 100).
- moisture_live=name [required]
- Raster map containing live fuel moisture (%)
- Name of an existing raster map layer in the user's current mapset search path containing live (herbaceous) fuel moisture (percentage content multiplied by 100).
- velocity=name
- Raster map containing midflame wind velocities (ft/min)
- Name of an existing raster map layer in the user's current mapset search path containing wind velocities at half of the average flame height (feet/minute).
- direction=name
- Name of raster map containing wind directions (degree)
- Name of an existing raster map layer in the user's current mapset search path containing wind direction, clockwise from north (degree).
- slope=name
- Name of raster map containing slope (degree)
- Name of an existing raster map layer in the user's current mapset search path containing topographic slope (degree).
- aspect=name
- Raster map containing aspect (degree, CCW from E)
- Name of an existing raster map layer in the user's current mapset search path containing topographic aspect, counterclockwise from east (GRASS convention) in degrees.
- elevation=name
- Raster map containing elevation (m, required for spotting)
- Name of an existing raster map layer in the user's current mapset search path containing elevation (meters). Option is required from spotting distance computation (when spotting_distance option is provided)
- base_ros=name [required]
- Output raster map containing base ROS (cm/min)
- Base (perpendicular) rate of spread (ROS)
- max_ros=name [required]
- Output raster map containing maximal ROS (cm/min)
- The maximum (forward) rate of spread (ROS)
- direction_ros=name [required]
- Output raster map containing directions of maximal ROS (degree)
- The direction of the maximal (forward) rate of spread (ROS)
- spotting_distance=name
- Output raster map containing maximal spotting distance (m)
- The maximal potential spotting distance (requires elevation raster map to be provided).
r.ros is part of the wildfire simulation toolset. Preparational
steps for the fire simulation are the calculation of the rate of spread (ROS)
with
r.ros, and the creating of spread map with
r.spread.
Eventually, the fire path(s) based on starting point(s) are calculated
with
r.spreadpath.
r.ros is used for fire (wildfire) modeling. The input is fuel model
and moisture and the outputs are rate of spread (ROS) values.
The module generates the base ROS value, maximum ROS value,
direction of the maximum ROS, and optionally the maximum potential spotting distance
of wildfire for each raster cell in the current geographic region.
These three or four raster map layers
serve as inputs for the r.spread module
which is the next step in fire simulation.
The r.ros module and two related modules
r.spread,
and r.spreadpath can be used
not only for wildfire modeling but also generally
to simulate other events where spread of something is involved and
elliptical spread is appropriate.
The calculation of the two ROS values for each raster cell is based on the
Fortran code by Pat Andrews (1983) of the Northern Forest Fire Laboratory,
USDA Forest Service. The direction of the maximum ROS results from the
vector addition of the forward ROS in wind direction and that in upslope
direction. The spotting distance, if required, will be calculated by a
separate function, spot_dist(), which is based on Lathrop and Xu (in preparation),
Chase (1984) and Rothermel (1991). More information
on r.ros and r.spread can be found in Xu (1994).
The output parameter is a basename (prefix) for all generated
raster maps and each map gets a unique suffix:
.base
for the base (perpendicular) ROS (cm/minute)
.max
for the maximum (forward) ROS (cm/minute),
.maxdir
for the direction of the maximum
ROS, clockwise from north (degree), and optionally
.spotdist
for the maximum potential
spotting distance (meters).
So, if the output parameter is blackforest_ros
, r.ros creates
blackforest_ros.base
, blackforest_ros.max
,
blackforest_ros.maxdir
,
and (optionally) blackforest_ros.spotdist
raster maps.
If only one or two of the options moisture_1h, moisture_10h,
and moisture_100h are given, the module will assign
values to the missing option using the formula:
moisture_100h = moisture_10h + 1 = moisture_1h + 2
However, at least one of them should be given.
Options velocity
and direction must be both given or both omitted.
If none is given, the module will assume a no-wind
condition.
Options slope and aspect must be also given together.
If none is given, the module will assume a
topographically flat condition. Option
elevation must be given if -s (spotting) flag is used.
Assume we have inputs, the following generates ROSes and spotting distances:
r.ros -s model=fire_model moisture_1h=1hour_moisture moisture_live=live_moisture \
velocity=wind_speed direction=wind_direction \
slope=slope aspect=aspect elevation=elevation output=ros
- r.ros is supposed to be run before running
r.spread module.
The combination of these two modules forms
a simulation of the spread of wildfires.
- The user should be sure that the inputs to
r.ros are in proper units.
- The output units for the base and maximum ROSes are in cm/minute
rather than ft/minute, which is due to that a possible zero ft/minute base
ROS value and a positive integer ft/minute maximum ROS would result in
calculation failure in the
r.spread module.
As far as the user just use r.ros together with
r.spread, there is no need to
concern about these output units.
- Albini, F. A., 1976, Computer-based models of wildland fire behavior:
a user's manual, USDA Forest Service, Intermountain Forest and Range Experiment
Station, Ogden, Utah.
- Andrews, P. L., 1986, BEHAVE: fire behavior prediction and fuel
modeling system -- BURN subsystem, Part 1, USDA Forest Service, Intermountain
Research Station, Gen. Tech. Rep. INT-194, Ogden, Utah.
- Chase, Carolyn, H., 1984, Spotting distance from wind-driven
surface fires -- extensions of equations for pocket calculators, US Forest
Service, Res. Note INT-346, Ogden, Utah.
- Lathrop, Richard G. and Jianping Xu, A geographic information
system-based approach for calculating spotting distance. (in preparation)
- Rothermel, R. E., 1972, A mathematical model for predicting
fire spread in wildland fuels, USDA Forest Service, Intermountain Forest
and Range Experiment Station, Res. Pap. INT-115, Ogden, Utah.
- Rothermel, Richard, 1991, Predicting behavior and size of crown
fires in the northern Rocky Mountains, US Forest Service, Res. Paper INT-438,
Ogden, Utah.
- Xu, Jianping, 1994, Simulating the spread of wildfires using
a geographic information system and remote sensing, Ph. D. Dissertation,
Rutgers University, New Brunswick, Jersey
(ref).
g.region,
r.slope.aspect,
r.spread,
r.spreadpath
Sample data download:
firedemo.sh
(run this script within the "Fire simulation data set" project).
Jianping Xu, Center for Remote Sensing and Spatial Analysis, Rutgers University.
SOURCE CODE
Available at:
r.ros source code
(history)
Latest change: Tuesday Dec 17 20:17:20 2024 in commit: ab90c5e5a9b668894da360fa97ffd4a51a38931e
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GRASS Development Team,
GRASS GIS 8.5.0dev Reference Manual