Provided by: grass-doc_6.4.3-3_all 
NAME
r.ros - Generates three, or four raster map layers showing 1) the base (perpendicular)
rate of spread (ROS), 2) the maximum (forward) ROS, 3) the direction of the maximum ROS,
and optionally 4) the maximum potential spotting distance.
KEYWORDS
raster, fire
SYNOPSIS
r.ros
r.ros help
r.ros [-vs] model=string [moisture_1h=string] [moisture_10h=string]
[moisture_100h=string] moisture_live=string [velocity=string] [direction=string]
[slope=string] [aspect=string] [elevation=string] output=string [--overwrite]
[--verbose] [--quiet]
Flags:
-v
Run verbosely
-s
Also produce maximum SPOTTING distance
--overwrite
Allow output files to overwrite existing files
--verbose
Verbose module output
--quiet
Quiet module output
Parameters:
model=string
Name of raster map containing fuel MODELs
moisture_1h=string
Name of raster map containing the 1-HOUR fuel MOISTURE (%)
moisture_10h=string
Name of raster map containing the 10-HOUR fuel MOISTURE (%)
moisture_100h=string
Name of raster map containing the 100-HOUR fuel MOISTURE (%)
moisture_live=string
Name of raster map containing LIVE fuel MOISTURE (%)
velocity=string
Name of raster map containing midflame wind VELOCITYs (ft/min)
direction=string
Name of raster map containing wind DIRECTIONs (degree)
slope=string
Name of raster map containing SLOPE (degree)
aspect=string
Name of raster map containing ASPECT (degree, anti-clockwise from E)
elevation=string
Name of raster map containing ELEVATION (m) (required w/ -s)
output=string
Name of raster map to contain results (several new layers)
DESCRIPTION
r.ros generates the base ROS value, maximum ROS value, direction of the maximum ROS, and
optionally the maximum potential spotting distance of a wildfire for each raster cell in
the current geographic region. 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). These three or four
raster map layers serve as inputs for another GRASS raster program r.spread. More
information on r.ros and r.spread can be found in Xu (1994).
Parameters:
model=name
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
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
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
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
Name of an existing raster map layer in the user's current mapset search path
containing live (herbaceous) fuel fuel moisture (percentage content multiplied by
100).
velocity=name
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 an existing raster map layer in the user's current mapset search path
containing wind direction, clockwise from north (degree).
slope=name
Name of an existing raster map layer in the user's current mapset search path
containing topographic slope (degree).
aspect=name
Name of an existing raster map layer in the user's current mapset search path
containing topographic aspect, counter-clockwise from east (GRASS convention)
(degree).
elevation=name
Name of an existing raster map layer in the user's current mapset search path
containing elevation (meters).
output=name
Prefix of new raster map layers in the user's current mapset to contain
1) the base (perpendicular) ROS (cm/minute);
2) the maximum (forward) ROS (cm/minute),
3) the direction of the maximum ROS, clockwise from north (degree), and optionally
4) the maximum potential spotting distance (meters).
If 'my_ros' is given as the output name, then r.ros automatically assigns
'my_ros.base', 'my_ros.max', 'my_ros.maxdir', and optionally, ’my_ros.spotdist' as
the names for the actual output map layers.
OPTIONS
r.ros can be run either non-interactively or interactively. The program is run
interactively if the user types r.ros without specifying flag settings and parameter
values on the command line. In this case, the user will be prompted for input. The program
will be run non-interactively if the user specifies the names of raster map layers and any
desired options on the command line, using the form:
r.ros [-vs] model=name [moisture_1h=name] [moisture_10h=name] [moisture_100h=name]
moisture_live=name [velocity=name] [direction=name] [slope=name] [aspect=name]
[elevation=name] output=name
If the options moisture_1h=name, moisture_10h=name, and moisture_100h=name are partially
given, the program 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=name and direction=name
must be in pair, whether given or not. If none is given, the program will assume a no-wind
condition. Options slope=name and aspect=name must be in pair, whether given or not. If
none is given, the program will assume a topographically flat condition. Option
elevation=name must be given if -s option is used.
EXAMPLE
Assume we have inputs, the following generates ROSes and spotting distances:
r.ros -vs model=fire_model moisture_1h=1hour_moisture moisture_live=live_moisture
velocity=wind_speed direction=wind_direction slope=slope aspect=aspect elevation=elevation
output=my_ros
NOTES
1. r.ros is supposed to be run before running another GRASS program r.spread. The
combination of the two forms a simulation of the spread of wildfires.
2. The inputs to r.ros should be in proper units.
3. 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 program.
4. The user needs to provide only ONE output name even the program actually generates
THREE or FOUR map layers.
5. The rules for optional parameters must be followed.
SEE ALSO
g.region, r.slope.aspect, r.spread
REFERENCES
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, New
Jersey.
AUTHOR
Jianping Xu, Center for Remote Sensing and Spatial Analysis, Rutgers University.
Last changed: $Date: 2009-05-23 01:12:36 -0700 (Sat, 23 May 2009) $
Full index
© 2003-2013 GRASS Development Team