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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).

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 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.

EXAMPLES

       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

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 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.

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, 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" location.

AUTHOR

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

       Last changed: $Date: 2014-10-27 16:35:33 +0100 (Mon, 27 Oct 2014) $

SOURCE CODE

       Available at: r.ros source code (history)

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