[R-sig-Geo] bottom area of a lake calculation

[sophie@lebl@@c m@ili@g off @euf@fr]

<span style="font-family:arial,helvetica,sans-serif; font-size:12px">‌</span>Dear all,<br>
<br>
I would like to calculate the bottom area of a lake. I have already used marmap to calculate projected area, i.e. surface area.<br>
But i have not found anything to calculate a non projected area. I have the coordinates of points (longitude, latitude and depth) I can convert them into xyz. But then I don't know how to calculate the surface I have found polygonal area calculation but I have a 3D object, a polyheron and I think I can not use polygonal area.<br>
Do you have any idea? do you know an R package that could help?<br>
<br>
thanks,<br>
Sophie Leblanc<br>
<br>
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