For comparison with other dataset, I'm calculating the LS factor using the following formula in ArcGIS:
(1) LS = Power(“flow accumulation”*[cell resolution]/22.1,0.4)*Power(Sin(“slope of degree”*0.01745))/0.09, 1.4)*1.4
but I was not able to find the theoretical formulation of LS it corresponds, I've got the feeling that (1) is the ArcGIS correspective of
(2) LS = (m+1) [ (U/22.13)]^m [sin(slope)/sin(5°)]^n
where U is the unitary upslope contributing area and (2) should be LS factor according to Mitasova et al. (1996) paper.
The following document
http://www.caee.utexas.edu/prof/maidment/giswr2014/ProjectReport/Kim.pdf
seems to support my feelings but in absence of references for (1) in literature I'm not completely sure that (1) and (2) are the "same" formula.
Mitasova H., Hofierka, J., Zlocha, M. & Iverson, L.R. (1996) Modeling topographic potential for erosion and deposition using GIS. International Journal of Geographical Information Science. 10 (5), 629-641.
Here are some more sources that you might find useful: http://gis4geomorphology.com/ls-factor-in-rusle/
In Raster calculator: type the below formula:
Int(Con("slope_INT" < 1,Power(("near_int_res" )/ (22.13),0.2) * (0.065 + 0.045 * "slope_INT" + 0.065 * Power("slope_INT",2)),0)) + Int(Con(("slope_INT" > 1) & ("slope_INT" 3.5) & ("slope_INT" 5,Power(("near_int_res" )/ (22.13),0.5) * (0.065 + 0.045 * "slope_INT" + 0.065 * Power("slope_INT",2)),0))
thank you Dear Hussein El Hage Hassan , I just want to know what is the role of the Int function and why you have added ,0)) ?
best regards
But for exemple in some softwares we have other formulas like Nearing, Mc cool, Weischmeier....
I have dealth with this in our last paper. If you still interested in see: https://www.researchgate.net/publication/341523003_Possibilities_of_including_surface_runoff_barriers_in_the_slope-length_factor_calculation_in_the_GIS_environment_and_its_integration_in_the_user-friendly_LS-RUSLE_tool
Best Regards
Jiri
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