RUSLE -- how to set up the control specifications

Hello,

I'm very new to the IDRISI and I was trying to do a soil erosion analysis on a 100 x 100-kilometer area with the RUSLE module, I have had all the necessary input images ready but I'm not sure how to determine the thresholds for slope, aspect, slope length, and smallest patch size in the "Control Specifications" box.

I was informed that the "Maximum slope length" needs to be set to 198.0294 feet, does that mean I should set the "Smallest patch size" to at least (198.0294)^2 square feet? However after entering parameters as so the module seems to forever stuck on "working" and no result or message of any sort appeared. Is there something wrong with my parameters, or is it simply that the calculation was too large to handle?

Could anyone help me with this matter? Looking forward to hear from you, thanks!

Clark Labs March 31, 2014 20:02

Lewei,

In most cases the patch size is not related to the max. slope length. Please review the Help for the module for detail. Patch size is related to the aggregation process of similar patches, as defined by the slope and aspect thresholds. The Help and Tutorial reference material that was used to develop the module. We strongly urge you to review these materials to successfully run your analysis, especially Renard et al. 1997.

RUSLE is an intensive operaiton, so depending on the size of your input data, the analysis could take a very long time to run. One alternative is to run some initial tests on lower resolution data or a window of your original before running the entire dataset.

Regards,

James Toledano

Clark Labs

RUSLE -- how to set up the control specifications

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