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r.ros(1)		    GRASS GIS User's Manual		      r.ros(1)

NAME
       r.ros  -	Generates rate of spread raster	maps.
       Generates three,	or four	raster map layers showing the base (perpendic-
       ular) 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]	[mois-
       ture_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]    [--over-
       write]  [--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=nameA [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 (percent-
	   age 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  (percent-
	   age content multiplied by 100).

       moisture_live=nameA [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  (de-
	   gree).

       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=nameA [required]
	   Output raster map containing	base ROS (cm/min)
	   Base	(perpendicular)	rate of	spread (ROS)

       max_ros=nameA [required]
	   Output raster map containing	maximal	ROS (cm/min)
	   The maximum (forward) rate of spread	(ROS)

       direction_ros=nameA [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).

DESCRIPTION
       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 maxi-
       mum  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 Lab-
       oratory,	 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 cal-
       culated by a separate function, spot_dist(), which is based on  Lathrop
       and  Xu	(in preparation), Chase	(1984) and Rothermel (1991).  More in-
       formation 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:

	   o   .base for the base (perpendicular) ROS (cm/minute)

	   o   .max for	the maximum (forward) ROS (cm/minute),

	   o   .maxdir	for  the  direction of the maximum ROS,	clockwise from
	       north (degree), and optionally

	   o   .spotdist for the maximum potential spotting distance (meters).

       So, if the output parameter is blackforest_ros, r.ros creates blackfor-
       est_ros.base, blackforest_ros.max, blackforest_ros.maxdir, and (option-
       ally) blackforest_ros.spotdist raster maps.

       If only one or two of the options moisture_1h, moisture_10h, and	 mois-
       ture_100h  are  given, the module will assign values to the missing op-
       tion 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.

EXAMPLES
       Assume  we have inputs, the following generates ROSes and spotting dis-
       tances:
       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

NOTES
       1      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.

       2      The user should be sure that the inputs to r.ros are  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 maxi-
	      mum ROS would result in calculation failure in the r.spread mod-
	      ule.   As	far as the user	just use r.ros together	with r.spread,
	      there is no need to concern about	these output units.

REFERENCES
	   o   Albini, F. A., 1976, Computer-based models of wildland fire be-
	       havior:	a  user's  manual,  USDA Forest	Service, Intermountain
	       Forest and Range	Experiment Station, Ogden, Utah.

	   o   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.

	   o   Chase,  Carolyn,	 H.,  1984, Spotting distance from wind-driven
	       surface fires --	extensions of equations	 for  pocket  calcula-
	       tors, US	Forest Service,	Res. Note INT-346, Ogden, Utah.

	   o   Lathrop,	 Richard  G. and Jianping Xu, A	geographic information
	       system-based approach for calculating  spotting	distance.  (in
	       preparation)

	   o   Rothermel,  R.  E.,  1972,  A mathematical model	for predicting
	       fire spread in wildland fuels, USDA Forest Service,  Intermoun-
	       tain  Forest  and  Range	Experiment Station, Res. Pap. INT-115,
	       Ogden, Utah.

	   o   Rothermel, Richard, 1991, Predicting behavior and size of crown
	       fires  in the northern Rocky Mountains, US Forest Service, Res.
	       Paper INT-438, Ogden, Utah.

	   o   Xu, Jianping, 1994, Simulating the spread of wildfires using  a
	       geographic  information	system and remote sensing, Ph. D. Dis-
	       sertation, Rutgers University, New Brunswick, Jersey (ref).

SEE ALSO
	g.region, r.slope.aspect, r.spread, r.spreadpath Sample	data download:
       firedemo.sh  (run this script within the	"Fire simulation data set" lo-
       cation.

AUTHOR
       Jianping	Xu, Center for Remote Sensing and  Spatial  Analysis,  Rutgers
       University.

SOURCE CODE
       Available at: r.ros source code (history)

       Main  index  | Raster index | Topics index | Keywords index | Graphical
       index | Full index

       A(C) 2003-2020 GRASS Development	Team, GRASS GIS	7.8.4 Reference	Manual

GRASS 7.8.4							      r.ros(1)

NAME | KEYWORDS | SYNOPSIS | DESCRIPTION | EXAMPLES | NOTES | REFERENCES | SEE ALSO | AUTHOR | SOURCE CODE

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