I have a DEM of a mountainous region. I'd like to extract the areas of the DEM above which 60% of the total DEM area lies. So, essentially I'd like to extract the areas representing upper portions of the mountains.
I've heard of this referred to as the hypsometric line (H60 line), but haven't been able to locate any documentation on how to achieve it.
My instinct is to somehow calculate the statistics of the DEM to tell me where the 60%-level is and then contour the DEM at this elevation. I can then clip the DEM by this contour and perform my calculations on the output DEM subsets.
So, my question is, how do I determine this 60% level?