I am trying to get the polygon of a basin boundary using R. I got a 7.5 arcsec DEM that I download from this page: https://topotools.cr.usgs.gov/gmted_viewer/viewer.htm
I look through a lot of websites and papers where I found that it is possible but not a with a clear example of how to implemented. In this paper: http://confluence-jwsm.ca/index.php/jwsm/article/view/2/1 ; they use RSAGA package to get the boundary but I have found no function to that in the package.
Does anybody know how to do this ??