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How to modify the script of SDR model

Hello everyone~
    I am preparing to use SDR model. But the cover management factor (C) is just determined according to the LULC type, which is relatively simple. If it is possible to modify the script, in order to use the factor C provided by user? and where to find the original script?

    Thanks a lot.



  • PerrinePerrine Moderator, NatCap Staff
    Hi Cao, 

    Are you suggesting to have a raster of the C factors as an input?
    We have explored this option for another project but I'm not sure the script is readily available. You'd need to find the line in the code where the model creates the C factor layer based on the LULC layer and the biophysical table.

    Btw, if my understanding is correct, I'd be interested in your methods to obtain the raster of C factors based on NDVI or other remotely sensed data. Feel free to share them here if it's possible at this stage.


  • RichRich Administrator, NatCap Staff

    Please note and excuse that we don't have a lot of support for external InVEST development at the moment. But if you have experience with Python development we'd love for you to try.  The README in our repo will be helpful for setting up dependencies and a build environment.  (

    And like Perrine mentioned, we're exploring methods to derive biophysical from raw remote sensed data.  The current bottleneck is methodological, not programming so it could be very helpful if you have any info you'd like to share. I think the landcover to biophysical table was a decent approximation a decade ago, but we're ready to move beyond that now. :)
  • Hi,
       thanks a lot. The methodology is as follows:

    Cai, C.F., Ding, S.W., Shi, Z.H., Huang, L., Zhang, G.Y., 2000. Study of applying USLE and geographical information system IDRISI to predict soil erosion in small watershed. J. Soil Water Conserv. 14 (2), 19–24 (in Chinese with English abstract).
    Lufafa, A., Tenywa, M.M., Isabirye, M., Majaliwa, M.J.G., Woomer, P.L., 2003. Prediction of soil erosion in a Lake Victoria basin catchment using a GIS-based Universal Soil Loss model. Agric. Syst. 76, 883–894.
    445 x 490 - 64K
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