topic Re: LS factor question in Spatial Data Science Questions

LS factor question

MS10 — Tue, 24 May 2016 09:30:35 GMT

Hi, i'm using the follow equation to create an LS factor for RUSLE, if anyone has used a similar equation did they divide the output by 10 or 100?

LS = Power(FlowAccumulation * 50 / 22.1, 0.4) * Power(Sin(Slope * 0.01745) / 0.09, 1.4) * 1.4

It has been used in studies [1,2] and my results seem more accurate when dividing by 10.

Thanks.

[1] Prasannakumar, V., Vijith, H., Abinod, S., Geetha, N. 2012. Estimation of soil erosion risk within a small mountainous sub-watershed in Kerala, India using Revised Universal Soil Loss Equation (RUSLE) and geo-information technology. Geoscience Frontiers, 3(2), pp. 209-215.

[2] Parveen, R., Kumar, U. 2012. Integrated Approach of Universal Soil Loss Equation (USLE) and Geographical Information System (GIS) for Soil Loss Risk Assessment in Upper South Koel Basin, Jharkhand. Journal of Geographic Information System. 4, pp. 588-596.

Re: LS factor question

DanPatterson_Retired — Tue, 24 May 2016 09:42:44 GMT

This comment has arisen before

https://community.esri.com/message/254894#comment-254894

You would be advised to go through all the threads on GeoNet using ... usle or rusle as key word searches

There are many and most come down to using the wrong formulation for slope (ie in degrees or % rise), if the slope is given as %rise (% change) then an obvious division by 100 would make sense to get rid of the % sign. Check the original references to and those on GeoNet to see how universal the expression is.

Re: LS factor question

MS10 — Tue, 24 May 2016 10:05:51 GMT

The original Slope raster was in degrees, however it is converted to radians in the equation. I originally divided by 100 so may stick with that.

Re: LS factor question

Munuvelu_vese — Fri, 10 Mar 2023 12:47:28 GMT

why did you divide it with 100? can you please be more specific.