1r.ros(1) GRASS GIS User's Manual r.ros(1)
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6 r.ros - Generates rate of spread raster maps.
7 Generates three, or four raster map layers showing the base (perpendic‐
8 ular) rate of spread (ROS), the maximum (forward) ROS, the direction of
9 the maximum ROS, and optionally the maximum potential spotting distance
10 for fire spread simulation.
11
13 raster, fire, spread, rate of spread, hazard, model
14
16 r.ros
17 r.ros --help
18 r.ros model=name [moisture_1h=name] [moisture_10h=name] [mois‐
19 ture_100h=name] moisture_live=name [velocity=name] [direction=name]
20 [slope=name] [aspect=name] [elevation=name] base_ros=name
21 max_ros=name direction_ros=name [spotting_distance=name] [--over‐
22 write] [--help] [--verbose] [--quiet] [--ui]
23 Flags:
25 --overwrite
26 Allow output files to overwrite existing files
27 --help
29 Print usage summary
30 --verbose
32 Verbose module output
33 --quiet
35 Quiet module output
36 --ui
38 Force launching GUI dialog
39 Parameters:
41 model=name [required]
42 Raster map containing fuel models
43 Name of an existing raster map layer in the user’s current mapset
44 search path containing the standard fuel models defined by the USDA
45 Forest Service. Valid values are 1-13; other numbers are recognized
46 as barriers by r.ros.
47 moisture_1h=name
49 Raster map containing the 1-hour fuel moisture (%)
50 Name of an existing raster map layer in the user’s current mapset
51 search path containing the 1-hour (<.25") fuel moisture (percentage
52 content multiplied by 100).
53 moisture_10h=name
55 Raster map containing the 10-hour fuel moisture (%)
56 Name of an existing raster map layer in the user’s current mapset
57 search path containing the 10-hour (.25-1") fuel moisture (percent‐
58 age content multiplied by 100).
59 moisture_100h=name
61 Raster map containing the 100-hour fuel moisture (%)
62 Name of an existing raster map layer in the user’s current mapset
63 search path containing the 100-hour (1-3") fuel moisture (percent‐
64 age content multiplied by 100).
65 moisture_live=name [required]
67 Raster map containing live fuel moisture (%)
68 Name of an existing raster map layer in the user’s current mapset
69 search path containing live (herbaceous) fuel moisture (percentage
70 content multiplied by 100).
71 velocity=name
73 Raster map containing midflame wind velocities (ft/min)
74 Name of an existing raster map layer in the user’s current mapset
75 search path containing wind velocities at half of the average flame
76 height (feet/minute).
77 direction=name
79 Name of raster map containing wind directions (degree)
80 Name of an existing raster map layer in the user’s current mapset
81 search path containing wind direction, clockwise from north
82 (degree).
83 slope=name
85 Name of raster map containing slope (degree)
86 Name of an existing raster map layer in the user’s current mapset
87 search path containing topographic slope (degree).
88 aspect=name
90 Raster map containing aspect (degree, CCW from E)
91 Name of an existing raster map layer in the user’s current mapset
92 search path containing topographic aspect, counterclockwise from
93 east (GRASS convention) in degrees.
94 elevation=name
96 Raster map containing elevation (m, required for spotting)
97 Name of an existing raster map layer in the user’s current mapset
98 search path containing elevation (meters). Option is required from
99 spotting distance computation (when spotting_distance option is
100 provided)
101 base_ros=name [required]
103 Output raster map containing base ROS (cm/min)
104 Base (perpendicular) rate of spread (ROS)
105 max_ros=name [required]
107 Output raster map containing maximal ROS (cm/min)
108 The maximum (forward) rate of spread (ROS)
109 direction_ros=name [required]
111 Output raster map containing directions of maximal ROS (degree)
112 The direction of the maximal (forward) rate of spread (ROS)
113 spotting_distance=name
115 Output raster map containing maximal spotting distance (m)
116 The maximal potential spotting distance (requires elevation raster
117 map to be provided).
118
120 r.ros is part of the wildfire simulation toolset. Preparational steps
121 for the fire simulation are the calculation of the rate of spread (ROS)
122 with r.ros, and the creating of spread map with r.spread. Eventually,
123 the fire path(s) based on starting point(s) are calculated with
124 r.spreadpath.
125 r.ros is used for fire (wildfire) modeling. The input is fuel model and
127 moisture and the outputs are rate of spread (ROS) values. The module
128 generates the base ROS value, maximum ROS value, direction of the maxi‐
129 mum ROS, and optionally the maximum potential spotting distance of
130 wildfire for each raster cell in the current geographic region. These
131 three or four raster map layers serve as inputs for the r.spread module
132 which is the next step in fire simulation.
133 The r.ros module and two related modules r.spread, and r.spreadpath can
135 be used not only for wildfire modeling but also generally to simulate
136 other events where spread of something is involved and elliptical
137 spread is appropriate.
138 The calculation of the two ROS values for each raster cell is based on
140 the Fortran code by Pat Andrews (1983) of the Northern Forest Fire Lab‐
141 oratory, USDA Forest Service. The direction of the maximum ROS results
142 from the vector addition of the forward ROS in wind direction and that
143 in upslope direction. The spotting distance, if required, will be cal‐
144 culated by a separate function, spot_dist(), which is based on Lathrop
145 and Xu (in preparation), Chase (1984) and Rothermel (1991). More
146 information on r.ros and r.spread can be found in Xu (1994).
147 The output parameter is a basename (prefix) for all generated raster
149 maps and each map gets a unique suffix:
150 · .base for the base (perpendicular) ROS (cm/minute)
152 · .max for the maximum (forward) ROS (cm/minute),
154 · .maxdir for the direction of the maximum ROS, clockwise from
156 north (degree), and optionally
157 · .spotdist for the maximum potential spotting distance (meters).
159 So, if the output parameter is blackforest_ros, r.ros creates blackfor‐
161 est_ros.base, blackforest_ros.max, blackforest_ros.maxdir, and (option‐
162 ally) blackforest_ros.spotdist raster maps.
163 If only one or two of the options moisture_1h, moisture_10h, and mois‐
165 ture_100h are given, the module will assign values to the missing
166 option using the formula:
167 moisture_100h = moisture_10h + 1 = moisture_1h + 2
168 However, at least one of them should be given.
169 Options velocity and direction must be both given or both omitted. If
171 none is given, the module will assume a no-wind condition.
172 Options slope and aspect must be also given together. If none is
174 given, the module will assume a topographically flat condition. Option
175 elevation must be given if -s (spotting) flag is used.
176
178 Assume we have inputs, the following generates ROSes and spotting dis‐
179 tances:
180 r.ros -s model=fire_model moisture_1h=1hour_moisture moisture_live=live_moisture \
181 velocity=wind_speed direction=wind_direction \
182 slope=slope aspect=aspect elevation=elevation output=ros
183
185 1 r.ros is supposed to be run before running r.spread module. The
186 combination of these two modules forms a simulation of the
187 spread of wildfires.
188 2 The user should be sure that the inputs to r.ros are in proper
190 units.
191 3 The output units for the base and maximum ROSes are in cm/minute
193 rather than ft/minute, which is due to that a possible zero
194 ft/minute base ROS value and a positive integer ft/minute maxi‐
195 mum ROS would result in calculation failure in the r.spread mod‐
196 ule. As far as the user just use r.ros together with r.spread,
197 there is no need to concern about these output units.
198
200 · Albini, F. A., 1976, Computer-based models of wildland fire
201 behavior: a user’s manual, USDA Forest Service, Intermountain
202 Forest and Range Experiment Station, Ogden, Utah.
203 · Andrews, P. L., 1986, BEHAVE: fire behavior prediction and fuel
205 modeling system -- BURN subsystem, Part 1, USDA Forest Service,
206 Intermountain Research Station, Gen. Tech. Rep. INT-194, Ogden,
207 Utah.
208 · Chase, Carolyn, H., 1984, Spotting distance from wind-driven
210 surface fires -- extensions of equations for pocket calcula‐
211 tors, US Forest Service, Res. Note INT-346, Ogden, Utah.
212 · Lathrop, Richard G. and Jianping Xu, A geographic information
214 system-based approach for calculating spotting distance. (in
215 preparation)
216 · Rothermel, R. E., 1972, A mathematical model for predicting
218 fire spread in wildland fuels, USDA Forest Service, Intermoun‐
219 tain Forest and Range Experiment Station, Res. Pap. INT-115,
220 Ogden, Utah.
221 · Rothermel, Richard, 1991, Predicting behavior and size of crown
223 fires in the northern Rocky Mountains, US Forest Service, Res.
224 Paper INT-438, Ogden, Utah.
225 · Xu, Jianping, 1994, Simulating the spread of wildfires using a
227 geographic information system and remote sensing, Ph. D. Dis‐
228 sertation, Rutgers University, New Brunswick, Jersey (ref).
229
231 g.region, r.slope.aspect, r.spread, r.spreadpath Sample data download:
232 firedemo.sh (run this script within the "Fire simulation data set"
233 location.
234
236 Jianping Xu, Center for Remote Sensing and Spatial Analysis, Rutgers
237 University.
238
240 Available at: r.ros source code (history)
241 Main index | Raster index | Topics index | Keywords index | Graphical
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244 © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
246GRASS 7.8.5 r.ros(1)