[R] how to derive true surface area from `computeContour3d' (misc3d package) -- follow up

j. van den hoff veedeehjay at googlemail.com
Fri Nov 8 16:11:08 CET 2013

On Fri, 08 Nov 2013 15:32:00 +0100, Barry Rowlingson  
<b.rowlingson at lancaster.ac.uk> wrote:

> On Fri, Nov 8, 2013 at 1:01 PM, j. van den hoff
> <veedeehjay at googlemail.com> wrote:
>> ps: it of course would still be nice, if the surface area (or a vector
>> containing the individual triangle areas)
>> were returned to the caller as well ...
>  Does the 'surfaceArea' function in the sp package do what you want?
> It's Edzer's integration of an R function that I wrote that calls some
> C code that someone else wrote that implements an algorithm from 2004.
>  You just need to coerce your grid data into the right form.

not quite, I believe: I need to compute the area of a (closed) iso-surface  
of a 3D object
defined by samples on a discrete 3D grid.
if I understand correctly from a quick view on `sp', `surfaceArea' does  
the surface integral of some function  z = f(x,y), instead.

but thanks for the pointer anyway, this might still be useful in a  
different context.


>  Barry


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