Emma wrote:
Is there a way to calculate from the DEM the total perimeter of
all lakes (+reservoirs, etc.)? In other words, I need to
calculate the total length of lake banks and so far could only
determine the total lakes area, which is of no use in this
case.
It's a fractal problem and so an impossible task to get the right
answer to. The best you can do is compare the relative perimeter
distances within the dataset (eg lake x has twice the shoreline
of lake y), but even then only if you can verify that the
original dataset is entirely consistent in its level of detail &
digitization.
which is to say, you're probably going to have to consider your
problem in another way.
maybe you could calculate the plan-area of the littoral strip in
a 5m(?) buffer around each one of the lakes and reservoirs?
Hamish