R script for automatic landslide length and width estimation based on the geometric processing of the bounding box and the geomorphometric analysis of DEMs

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#-----Landslides length and width estimation-v-01------------------
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#    The self-explanatory R script performs the analysis of 
#    landslide flow direction using 2 steps:
# 1. Generate the minimum-area oriented bounding box for every 
#    landslide polygon, and the corner points and midpoints for 
#    the bbox sides; add altitudes for the midpoints and compute
#    the square of the difference raised to the power of two.
# 2. Crop the DEM and compute flow length; extract the maximum
#    slope length. 
#    The landslide width and length are then estimated based on
#    the oriented along the flow direction bounding box.
#    Please cite the article bellow if you use this script.
#    Niculita Mihai, 2016, Automatic landslide length and width 
#    estimation based on the geometric processing of the bounding
#    box and the geomorphometric analysis of DEMs, Natural Hazards 
#    and Earth System Science, 16, 1-10, doi:10.5194/nhess-16-1-2016
#     !!! ATENTION !!! slope length is a computational demanding
#    operation so if you can please insert the slope length as a 
#    column in the landslide inventory shapefile (slMFD field).
#    *please also add an id field.
#    *see the attached shapefiles for a reference on the script
#    variables and use them to format your data.
#    *modify accordingly for any change in the input data.
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