1r.uslek(1) GRASS GIS User's Manual r.uslek(1)
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6 r.uslek - Computes USLE Soil Erodibility Factor (K).
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9 raster, hydrology, soil, erosion
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12 r.uslek
13 r.uslek --help
14 r.uslek psand=name pclay=name psilt=name pomat=name output=name
15 [--overwrite] [--help] [--verbose] [--quiet] [--ui]
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17 Flags:
18 --overwrite
19 Allow output files to overwrite existing files
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21 --help
22 Print usage summary
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24 --verbose
25 Verbose module output
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27 --quiet
28 Quiet module output
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30 --ui
31 Force launching GUI dialog
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33 Parameters:
34 psand=name [required]
35 Name of soil sand fraction raster map [0.0-1.0]
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37 pclay=name [required]
38 Name of soil clay fraction raster map [0.0-1.0]
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40 psilt=name [required]
41 Name of soil silt fraction raster map [0.0-1.0]
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43 pomat=name [required]
44 Name of soil organic matter raster map [0.0-1.0]
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46 output=name [required]
47 Name for output USLE K factor raster map [t.ha.hr/ha.MJ.mm]
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50 r.uslek calculates the USLE K factor, that is the Soil Erodibility Fac‐
51 tor. It takes input of soil texture classes (sand, clay, silt) and
52 organic matter, all in range of [0.0-1.0]. The FAO World Soil CD docu‐
53 mentation was used to produce the conversion system between soil tex‐
54 tures and soil classes. The soil classes are in number of 12 and appar‐
55 ently come from a USDA publication of 1951 (p.209). Once the soil
56 classes have been identified (by vector cross-products tests), a gen‐
57 eral conversion table was applied for transforming soil classes into K
58 factor.
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61 r.watershed provides for USLE L, S, LS factors.
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64 Calculate the USLE K factor (synthetic values, North Carolina sample
65 dataset):
66 # NC data: simulation
67 g.region rural_1m -p
68 r.mapcalc "sand = 0.11"
69 r.mapcalc "clay = 0.47"
70 r.mapcalc "silt = 0.42"
71 r.mapcalc "organ = 0.0136"
72 r.uslek psand=sand pclay=clay psilt=silt pomat=organ output=usle_k
73 r.univar usle_k
74 # Result: uslek = 0.25
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76 Example with small variations (condition: d_sand + d_clay + d_silt =>
77 1.0)
78 # NC data: simulation
79 r.mapcalc -s "sand_r = rand(0.09,0.13)"
80 r.mapcalc -s "clay_r = rand(0.45,0.49)"
81 r.mapcalc -s "silt_r = rand(0.40,0.44)"
82 r.mapcalc -s "organ = rand(0.01,0.70)"
83 r.mapcalc "temp_sum = sand_r + clay_r + silt_r"
84 r.mapcalc "sand = sand_r / temp_sum"
85 r.mapcalc "clay = clay_r / temp_sum"
86 r.mapcalc "silt = silt_r / temp_sum"
87 r.mapcalc "test = sand + clay + silt"
88 r.info -r test
89 g.remove -f rast name=sand_r,clay_r,silt_r,temp_sum,test
90 r.uslek psand=sand pclay=clay psilt=silt pomat=organ output=usle_k
91 r.univar usle_k
92 # Result: uslek = variable values
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95 r.usler, r.watershed
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98 Yann Chemin, SIC-ISDC, Turkmenistan
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101 Available at: r.uslek source code (history)
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103 Main index | Raster index | Topics index | Keywords index | Graphical
104 index | Full index
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106 © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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110GRASS 7.8.5 r.uslek(1)